Some things to consider - do you plan on keeping the Level 2 EVSE from Mini/BMW plugged into the outlet or do you plan to carry it in the car when driving ? Do want to be able to control the EVSE from an app - which would allow you to start, stop and view charging data from your mobile device ?
The Mini/BMW EVSE provided with the car will work fine, so maybe more of a convenience thing. We have two EVSEs in the garage. One is an Autel unit hardwired to a 60 amp breaker and another was a Chargepoint HomeFlex plugged into a NEMA 14-50 outlet. The ChargePoint died after about one year of use and getting a warranty replacement was like getting teeth pulled. Finally got the replacement, but opted to replace it with an additional Autel unit. The Chargepoint HomeFlex will work without WiFi, but it defaults to 16 amps. ChargePoint tech support rebooted the unit remotely for me, but after that, I could never complete the setup, as the units WiFi could not find any networks. The Autel has an ethernet port and a dip switch to manually set amp level, so it works fine without internet.
Haven't used the provided Mini/BMW EVSE as we got one of the "backward" units - when using the NEMA 14-50 plug, the front of the unit faces the wall. We already had the two EVSEs in the garage before our SE was delivered. We got the WiFi units because one of our previous plug in cars (2016 Chevy Volt) had an issue with its timer and since we get reduced rates between midnight and 6 am - it was either plug the car in at midnight or get a "smart" EVSE.
If you plan on plugging/unplugging the Mini/BMW EVSE on a regular basis, the current recommendation (from Tesla and Porsche anyway) is to use a commercial grade outlet like the Hubbell HBL9450A. These handle the constant plugging/unplugging of the EVSE better than the non commercial versions.