No I'm not but it's incredibly misleading generally and almost never has a significant enough sample size. Quality of opposition matters a lot, of course. But because we're talking about such a small sample size a bad lbw decision, declaration batting, dropped catches etc can have way too much impact. There are too many variables so you're better off having watched it and judging the encounter based on the eye test. Average in matches played against X is even more random. The only time it may make any sense is in Ashes tests over a long career.
This is going to be a super-long post, but let me go anyways.
By nature the sample size becomes small when you do a countrywide split of performance analysis, but people do it all the time. And a single good/bad innings can significantly affect country-wise stat as well. If Tendulkar hadn't scored 241* in the final Test in 2004 against Aus (he had pretty much failed that entire series until that knock), his career average in Australia would have fallen "great" to "good".
Despite that, on this forum as well as everywhere else, I often see people quoting how much a player averages in Australia to determine his quality. Even you do that, don't you?
Moreover when discussions get deep, it can get get more nuanced, and that's when these micro-filters (performance against certain bowlers etc.) can be applied, and for good reason.
For instance, let's take performance of Lara and Tendulkar in Australia. They both played in the same era, and Australian team was easily the best team of their era, and batting performance in Australia in that era is often used by many here as a yardstick for rating a batsman's greatness, because batting against that side in their backyard was genuinely tough.
Lara scored 1469 runs in 35 innings @41 runs per innings in Australia from 1992/93 to 2005/06
Tendulkar scored 1809 runs in 38(34) innings @53 runs per innings in Australia from 1991/92 to 2011/12
On paper, Tendulkar is clearly ahead, and if you exclude Tendulkar's last series in Australia because he was past his best (which also further overlaps Lara-Tendulkar's years of play in Australia) Tendulkar becomes way ahead. Tendulkar then has 1522 runs in 30(26) innings @58 runs per innings in Australia from 1991/92 to 2007/08. So Tendulkar was clearly a much better batsman than Lara in Australia.
Not just Tendulkar, when you tighten the era overlap, you will find that many other Indian batsmen - Sehwag, Laxman and Dravid - were all much better batsmen than Lara in Australia.
At least that is what the blanket stat of "performance in Australia" says.
But this blanket stat of performance of Lara and Tendulkar (and other Indian batsmen) in Australia is extremely misleading. It misses a factor, that, in my opinion, for sure would have changed things in a big way.
Of the 35 innings that Lara played in Australia, McGrath played in a whopping 27 of those.
Of the 30 innings that Tendulkar played in Australia (till 2008), McGrath played in just 6 of those.
And not just that, Tendulkar never once faced McGrath on genuinely fast bowler friendly Australian pitches (like Perth & Gabba of 90s) while Lara did it several times.
For example, If you look at the Australian fast bowling lineup that Lara faced in Test match at Perth in 2000-01, it reads McGrath, Gillespie and Lee. Combine the attack with the pitch, Tendulkar (and other Indian batsmen) never faced such a testing situation in Australia in his career.
In fact McGrath, Gillespie & Lee never ever bowled together to India even once, either in Australia or in India.
To me there is no comparison in average quality of Aussie attacks they faced in Australia. For me these factors are impossible to ignore when we talk about an "average in Australia" or "average vs Australia" comparison. That's the reason why I bring up "vs bowler" stats. BTW, this isn't just about Lara vs Tendulkar in Australia, this can also be said to some extent about several other batsmen of that era vs Tendulkar as well.
Because the moment you introduce McGrath into the equation, averages of Tendulkar and every Indian batsman come crashing down.
To me it would be absurd not to factor in presence/absence of McGrath in any comparison from that era. He was easily the greatest fast bowler of Tendulkar-Lara era. Without McGrath's presence - in that era - the Aussie attack became half of what it was. Warne was a non-factor for both Lara & Indian batsmen. If anything they all licked their lips when playing Warne (as Lara called him "lollipop bowler" whom he looked forward to playing). Even in 2005 Ashes that Australia lost, they never lost a single match in which McGrath participated.
McGrath's presence clearly made a good Aussie attack into a formidable one. BTW, the same applies to Wasim & Waqar in early to mid 90s as well. That's the reason - to me - vs bowler stat is a pretty big deal.
So even though Lara (or Kallis or Inzamam) & Tendulkar played in the same era, to me, it's like they played two completely different Aussie attacks when they visited Australia. Either a "stat-on-paper" comparison cannot be made because of the difference in quality of attacks and conditions, or McGrath factor has to be included in some way.