A couple of benefits to the apps: one is that you get exact information on the charging session.

The bigger benefit is that some charging stations will stop charging once your battery is "full", wait a bit, then start charging an idle rate. The app can notify you about this or you can be texted or both since the station knows who you are.

All EVs have a charging curve and typically the last 80% or 90% to full goes much more slowly than starting from 0% or 20%. In one case, ChargePoint decided that my Bolt EUV was charging too slowly and started charging me the idle rate without notifying me. Since the idle rate was $.25/minute, I ended up getting charged $1.50 or something like that. I didn't think the idle rate was unfair but I was literally waiting in a coffee shop for the car to get as charged as much as possible.