When I used it, I mostly switched between the 9 apps in my favorites/dock with the Meta+digit shortcuts. I rarely used anything besides those 9, and then I just used alt tab. It worked really well, no complaining.
Today it’s mostly the same, but with a tiling window manager and the same numbers: 3 is thunderbird, 5 is file browser for instance. It’s muscle memory at this point, feels great.