There's also the obvious compression use case. Assuming the rest of your code is sufficiently robust, you can shave off all the excess bits from your data stora

There's also the obvious compression use case. Assuming the rest of your code is sufficiently robust, you can shave off all the excess bits from your data storage. There may be a performance penalty, but you won't have to deal with low level ops or alignment issues. Most real world big data will exceed 32 bits (i.e., the identifiers will exceed 32 bits), but is nowhere close to 64 bits. The benefit is more meaningful if your data now fits in a cache/fast memory whereas it didn't before.