I dislike it because the autocompletions are hilariously brain-dead most of the time. Like, it usually autocompletes folder names correctly, but I can't really rely on that feature because some of them are never offered as candidates. E.g. "Work" is not only not offered as candidate (even though I have a folder named "Work"), but mysteriously autocompleted to "Word".
It's also a solution to a self-inflicted problem. Super-crowded Start menus were a problem, but not a very widespread one among people who aren't nerds. The Windows 11 Start menu is crowded but largely because it's littered with Microsoft's own apps. If I were to take out Xbox, Alarms & Clocks and all the other crap I no longer bother to uninstall because it's gonna come back on the next update anyway, I could probably use it quite comfortably.
Also, there is also a "discoverable" way to launch programs keyboard-only: <Windows>, P, A, C (Programs - Accessories - Calculator).
I just really dislike the Windows 10 start menu search. It slows down on random occasions just often enough to be too annoying for me to use, at least on my machine.