If someone wants in your house, they can almost always get in your house, so the programmable deadbolt seems just as secure in that sense. Houses just aren’t that strong.
It seems less likely for power issues to knock one out than for kids to lose a key, so I think accessibility would actually be in favor of the programmable model, right?
Thousands of people have pads for their garage doors and I don’t think it’s any more likely for people you don’t know to get in that way than any other. The problem comes from people you know but don’t necessarily want in there. As your kids get older this might include their friends.
Personally my main concern would be how easy it is to change the codes, if that’s simple, and I felt like I would actually change it every couple of months at least, then I think the programmable deadbolt is a great way to make sure your kids can get in when they need to while still letting you lock a door and not leave a spare key lying around under a welcome mat or flower pot.