iPad Mini 4 used. WiFi vs Unlocked.

Looking to get a used ipad mini 4 for just flying my drone and wondering what the difference between the WiFi and the Unlocked version? Looking at swappa.com the unlocked is going for $220 and the WiFi for $300 plus. I won't need the cellular part and don't plan on activating it but I can still use it on WiFi correct?

First, all iPads are unlocked. Even if you had the cellular version, SIM cards can be swapped between various carriers and it will still work OK as long as you pay the carrier for the data. So yes, you can use the WiFi anytime without worrying about any specific carrier. I did just that with my cellular iPad that I originally had from Verizon. I took out the Verizon SIM card and put in a T-Mobile SIM card that I bought from T-Mobile and used it that way for years before trading it in on a new iPad Pro.