>>95835034 (OP)Depends on the ruleset. Some games really lean into minis on grids. Savage Worlds is a notable example. You can go theater of the mind and it works fine, however, it is built on a skirmish game's skeleton so it shines much brighter with mini setup.
Hex for overland, squares for smaller areas by the way. Also, you should be able to see what's in every adjacent hex in a hexcrawl, it speeds the game up dramatically and encourages player exploration more.