Personally, yeah, I find it much less offensive if the extra purchases do not nag you in-game and their presence is not missed or noticed in terms of affecting balance.

For example, Middle Earth Shadow of War infamously let you buy Uruks. Having played the fuck out of that game I can confidently say the game was balanced such that you never needed to do that (apart from the end game grind, but the grind is the gameplay, so if you hit end game and didnt want to grind, you just didn't wanna keep playing), but having it appear in the menus was jarring and the idea of buying an Uruk with real money juxtaposed next to the mechanical intent of obtaining Uruks through exploration, marking, stalking, and exploiting their weaknesses just stuck out like a cynical sore thumb.

If they put the Uruk purchases outside the game with no in-game ads and I played through Shadow of War and was like "man holy shit, my Uruks cannot keep up with the curve, this is insanely grindy" and I discovered that you could buy them and skip it, I'd say thats dastardly as well.

But the happy medium would be balancing it so it wasn't necessary, but providing an external purchase to milk that revenue if they really still wanted to. That example is moot now anyway since they eventually removed the MTX Uruks entirely.