1) Just because some high stakes pros are doing something doesn't mean it'll win the most money in your games.
2) They don't 3b hands like A5s to autoprofit from folds. They 3b so their range isn't super face up and they're tougher to play against (and have a bit more board coverage) in 3b pots.
Imagine a player who only 3b AA + KK over a big sample -- any time they 3b, you could just fold...or take flops with some hands (to setmine, for example) and you'd know exactly what they had when you're trying to navigate postflop. But let's take an opponent who's 3b AA, KK, A5s, 97s, JTs...well they'll be much trickier to play against on a wide variety of flops, and they'll now sometimes be bluffing and sometimes vbetting post, which gives you trickier decisions than just knowing they only have AA/KK.
Is this sort of disguise important in your games? Who knows.
Also, if you only 3b a super value heavy 5%, they'll be able to open wider vs your bb because you don't put them in tough pre spots by 3b appropriately.
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I know in theory it should work cause we have blockers - so if they fold 60% to 3bet whenever we have hand like this they should have strong hands with lower frequency and hence fold even more so if they fold 66%+ we end up with immediate profit.
If someone is folding 60% to 3b, they're probably not folding 66%+ if you have A5. Yes, you have the A blocker, but you need to think about this more because you're missing something.