Pretty much every bank offers a bill pay service that automatically reverts to paper checks if the recipient can’t be paid electronically. Capital one 360 as well as my local credit unions have this feature.

Are there banks which don't offer that? That's been a standard feature for a long time.

I have used that with almost every bank, Discover, Wells Fargo, Chase, Capital One. Surprisingly, few of different banks looked like had same third party printer/mailer i.e. mailed from same address.

Just a tidbit, My work is paid by 1000s of Californians through these bill pay checks. Often we receive a thick stack (maybe 100) of these checks with sequencial serial numbers, same account & routing numbers, & each customer's unique identifier (for us to allocate money), all in same envelope or box. Its fun to go process those stacks.