Starling business accounts do allow cash deposits through the Post Office network but they're chargeable, like cash deposits on any business account I've seen.

Domestic ATM withdrawals are a cost for Starling as they have no network of their own; they're not even part of Link.

I'm not sure that the paltry interest they can gain from business deposits will be enough to make those accounts profitable (they just announced another £60m of funding this week).

I'm a relatively happy personal customer of Starling, so I'm not against them, but I do think it's a bit optimistic to say Starling's business accounts are profitable based on no evidence.