Is sanding past 320 overkill?

I mainly work with timber table tops and stair treads, I’ve never felt the need to sand beyond 320 grit. Despite reading advice on reddit from others who go up to 500 or even 1500 grit, I find it unnecessary. The finish—whether high gloss or satin—looks flawless, feels like silk, and has no visible swirl marks. Sanding beyond 320 just seems like a waste of time for timber.

Most of the time if I’m following instructions on the product finishes. I generally sand 100 grit, 120 and then as a super light sand at the end I finish it with either 180 Or 240 just so it feels smooth .

Rarely do I feel the need to even go to 320