Fido is my primary bank ... even more than they're my brokerage firm, and I've used a "linked" checking account since they were first offered.
The biggest advantage to me is that there's MUCH more activity in my FCR (i.e., checking) account than on the brokerage account side. So this provides a nice easy way to keep the minor number of brokerage transactions (primarily dividends) separated. Any dividends (stock or mutual fund) that aren't reinvested are then transferred to the checking account as deposits. Very straightforward. And Quicken automatically transfers any cash activity (including downloads) in the brokerage to the linked checking account. And, naturally, the linked checking account work just like any other checking account.
I really can't imagine inserting all of those banking transactions back into my brokerage register.