many possible and valid reasons to choose/use one or another ....... explaining all of them would be more piling up scenarios where one or the other is more adequate
anyhow, remark "if done properly" is there to point importance of comparing two equally good solutions when using particular constructions to evaluate principles, outlining stance that one is not better than other, it just can be more appropriate, either for intended context of use, or simply to listener's preferences
now, also important to outline factor that some balanced configurations are not having stellar performances*** when used in any SE scenario ( be it SE in , or SE out or whatever) simply as result of chosen approach to get to stellar performance when used fully balanced; just one factor more when evaluating
in short....... my stance in general - is that Bal is not superior to SE, nor SE is superior to Bal; horses for courses
***some Bal stages are having extremely low THD when used in native modus operandi ( Bal) while having sorta highish THD (even harmonics ) when used in non-native modus operandi ( SE)