I actually think that with bounded accuracy a point or two difference doesn’t matter, but it rather is felt more acutely on a purely emotional level.
There are arguments to be made in either direction. As you've said, the system is intended
to make it so that Advantage is worth so much more than other stuff, and is your one-stop buff shop, so you get that and you're done. Little point in grubbing for more benefits mechanically. And, on the feel side, hitting on a 16 when you would have missed, and doing 1 more average damage, is pretty small potatoes.
On the flipside, "Bounded Accuracy" only really works as a fitting term if it actually
means "bounded accuracy and defenses
," so that all of the numbers are bounded similarly. But, at least from my casual examination of the monsters in the books I've read, there's a pretty solid argument to be made, not for "this ONE SINGLE +1 will make ALL the difference," but rather that gunning for the highest AC and highest to-hit you can get makes an outsized difference in the long haul. Because if you can grub up just another +1 or +2 from somewhere, well, that net +3 difference may only matter in 15% of rolls you make, but it's very likely going to jump you up significantly
in terms of how many things you can hit with reasonable reliability. Then, from the perspective of feel and relative differences, fifteen percentage points is (very nearly) the difference between "hitting as often as you miss" and "hitting twice
as often as you miss." That could be a pretty huge deal, if the DM is using enemies that ride a bit high on the AC curve.
You can make similar arguments about the 4e method, where the numbers go up a lot and there's innate scaling. On the one hand, "you're on a treadmill," so you're incentivized to grub for whatever bonuses you can (which may be plentiful, if non-obvious) in order to "get ahead." On the other hand, the system bakes in the idea that there are plenty of monsters you simply couldn't hit even if you wanted to, so you only move the "how much of the DMG can I reliably hit now" meter up a small amount, and many of the best bonuses don't come from self-focused things (or are trivial to get, like spending one feat or picking a high-proficiency weapon) but rather from teamwork. Then, on the feel side, because the math is clearly laid out for you rather than aiming for 5e's kinda-sorta 'black box' approach, you can choose
where you want to end up--e.g., I like to build Dragonborn Paladins that don't
have 18 in either of their main stats, because I can compensate for that in other simple ways (use +3 proficiency swords, pick up a feat, grab an at-will with a hit bonus, etc.) and still end up with a perfectly viable character that is more of a generalist.
So...yeah. In the long run, I'm not actually sure that BA addresses either
the "feel" side OR the "math" side, unless you were kinda already inclined toward its perspective to begin with. It makes a different
situation, where the reasons for bonus-seeking change. But the reasons are still there, and (much to my chagrin) the over-use of Advantage induces its own problems.