I developed the "muscle memory" to use vi decades ago, and have been able to use it ever since, with minor hiccups like too-small ESC keys and the CTRL key moving to its present position on PC keyboards. vi everywhere. On the Amiga I used to have, on Unix boxes of all kinds including an ancient V7 one I played with for a while ("elvis" barely fit), over dialup terminals, over Raspberry Pi serial consoles, everywhere.

If instead you invest muscle memory in a custom hardware assist device, it's lost when you don't have that assist device. Getting used to insert mode vs. not insert mode is really not so bad.