Transitioning to Keyless Door Knob

[Alexa Potocki]

I'm looking into transitioning to keyless door entries for our rentals. Currently, I have the two-part doorknob which has a key for the knob and a key for the deadbolt. It seems it would be desirable for a keyless entry for our tenants and it makes switching the codes simple between tenancies. However, I can't seem to find what type of keyless door "knob" would best fit with the setup I currently have - I tried to illustrate with the picture below.

Has anyone else transitioned from this type of doorknob to coded doorknobs? What have you used? 

I can find ones with a coded deadbolt and a plain knob (no locking mechanism). Has anyone used these? Are tenants okay with just a deadbolt as the lock for the main entrance of the home? 

Thanks in advance for your input.

Alexa