You can still use those USB-C ports to charge the laptop if you want. The MagSafe port is just there in case you want to charge it very quickly, or use their custom cable that will help reduce the probability of the device accidentally being ripped off the table and dashed on the floor, if you should happen to trip over the cable.

I welcome the new MagSafe cable. IMO, they should never have gotten rid of it in the first place.