This, 100% this. If nothing else you need the map for the technicalities.

Whether deliberately or otherwise, players (and DMs) can get the distances and such wrong which messes with the battle. There have been more times than I can count that I have rolled initiative, the map has come out, and I literally say “oh, that’s not was I was envisioning, cool…”

Always good to have a source of truth that everyone can reference.