Is there any particular reason in single player not to scan the entire map? The tutorial seems to suggest that there is a sweet spot for cost vs knowledge but I cant seem to find any solid reason not to scan every inch of the map. What am I missing?

i was wondering that too. there seem to be no costs associated to the scans. the scans unpause for a short moment, sometimes the enemies place their bases during them. but other then that i see no downside.

Really? I hadnt even seen that... The best they ever did was sometimes they would plant right after me but seemingly never before. i wonder if its a difficulty setting, I am still mucking around in the practice games and campaign.

In practice battle 3-4 you will first see the AI dropping their bases before you finish scanning which means you will need to work fast to get the ressources claimed or the AI will kill you economically.

I'd recommend setting the game to reveal map if possible. The scanning mechanic adds nothing to the game, and noone in multi uses it anyway.