mgsafe to charge the iphone, it is not necessary to bring a magnetic protection case, if for the sake of safety performance, it can be brought, but most of them will not be a problem, if you have to buy the relatively formal mobile phone case is OK.
For example, if you buy a mobile phone case in the official channel, it will not affect the efficiency of charging, if the quality is relatively poor, it will certainly affect the charging efficiency
Yes, Apple's original magnetic design is no case charge