I also like having two institutions, since one of the biggest threats is ATM card skimming. More machines are moving to EMV, but it's trivial for someone to set up a fake ATM or skimmer, siphon up magstripe data and PINs, and drain accounts. While you are not responsible for fraud, most institutions will freeze the account for 30 days (which is legal) while they investigate.

If that checking account has money for your rent or credit card bills, it could be disastrous.

So I use a separate account at a separate institution for my "spending money". All I use it for is to withdraw money at ATMs.