That’s definitely a consideration. I took the “low key” (pun not intended) approach and got one of those fake rocks to hide a key in as a workaround in case we get locked out! It’s pretty easy to hide it in our yard, given the number of rocks etc we have.
I have one keyless knob on an interior door, and it is simply great. But it’s the exterior door, and it just seems to be one more protection, albeit a fairly weak one, to have two locks rather than one.
Ideally, if there were a keyless knob and deadbolt combo, I would have jumped on that. When I asked the fellow at Lowes about it today, he just laughed!