Small open-raising on the button when stealing? Idea and argument

Not sure what exactly you're getting at here.

If opponent 3bets us, his 3bet will usually be bigger vs a 3x raise than a 2.5x raise so its going to be bigger postflop.

Regardless of our raise size, our defending range should be constructed based on villains range. If villain is 3betting more often vs our 2.5x raising range, we are then able to defend wider because his 3bet range is wider.

In general, 2.5x allows us to open wider because the risk/reward ratio is lower. IF and only if, opponent adjusts by 3betting us wider, then we can readjust by defending wider. What I think you're saying is villain can get away with betting bigger and risking the same amount of bb. However, if his range for doing this is the same, our defending range shouldn't change much, the only difference is worse pot odds on the flop, but if opponent is 3betting the exact same range as he is vs our 3x raises then this should be mitigated by the extra blinds stolen.
When we flat his 3bet our initial raise is dead money so say he 3bets to 8bb after we raise 2.5x, we are calling 5.5 into 10.5 so we only need to win about 1/3 of the time after flat calling.

Remember that the steal success ratio advantage on the button is pretty hard to be negated by 3betting, if we only need our raise to work 62.5% of the time then this means opponent will only negate our raise as +EV if their combined 3bet is 38%. And a 19% 3bet range is very weak and hard to play OOP. We can probably fold to every 3bet most players make and still show a profit 3xing, but of course there are many hands that are +EV to defend vs a wide 3betting range IP.

many people just minraise the BTN these days. I raise x2.1 - so no one gets my minraising statistics in their HUD

in deepstack tournaments, open minraising any position a lot is good for creating a loose image

It seems to me that min-raise BTN is not a steal tactic, but an attempt to get to play post-flop, where presumably we can generate more value than we could get merely by stealing.

If it encourages weaker players to call wider, then our goal is accomplished, and we are now post-flop, in position vs a weaker player.

If we DON'T have the skills we need post-flop, then perhaps a 2.5x or 3x raise would be better. However raise/folding pre then merely costs us more.

Whatever the BTN open-raise size, people are still going to play roughly the same ranges, it seems to me.

Some good thought-provoking here.
--VS