I use PDK for my 39 unit building. I also doubted a mobile-only solution especially for these Class C residents so I issue one keyfob to each adult on the lease and promote mobile use as much as possible, especially to select third parties I grant access to the building. The fobs aren’t expensive but it can sometimes be more streamlined (and normal seeming to residents) than fumbling with your phone or the reasons mentioned above.
The ability to enable/disable access, and remotely unlock is revolutionary you’re going to love it. Another factor to consider is that my PDK system also integrates directly into my Turing camera system so there’s a video entry log tied to every access attempt/entry. It’s a nice to have if you have access control and video surveillance.
PDK does use email to authorize a phone token automatically, so if a resident replaces their phone it does resend them a new token they can use immediately as long as they are willing to accept the previous will be disabled.
PDK is not perfect, access is fast and flawless with cellular and battery backup, but the UI on the management side could be slightly better, I have a few annoyances. I do have door prop alarms enabled though so those make noise when left open. I also considered Brivo, Open Path and ButterflyMX and one thing I wish we had is the ability to grant visitor or vendor access via email. I ultimately chose PDK due to the video integration, and its competitiveness amongst all the other factors.
Sorry for the long review, I hope this helped. Looking back 12 months, I’m happy I chose a fob as primary with mobile as backup. Having mobile as primary would introduce a lot of problems everyone mentioned above and I agree could turn prospective residents away.