I too am on the fence with Wi-Fi locks, but do like the idea of not needing a key.
I don't own a keyless deadbolt but have been thinking about adding one for some time.
Mainly for at my cottage where I have forgotten keys for it a few times.
My daughter has a keyless deadbolt on her house and it has come in handy so many times for her.
I believe it is Bluetooth compatible but not Wi-Fi however they don't use that feature.
Keyless locks have been around for several years, automating them about as long starting with Zwave and Bluetooth.
So Wi-Fi isn't much different other then they may be easier to hack(just my opinion)
The deadbolt part would be no different then your regular dead bolt.
If your current deadbolt operates smoothly then you should have no issue if it is hard to turn then installing could be a bit of work.