Currently there are only 3 data types that can be used for syncing animator parameter :
bool > 1 bit
int > 8 bits
float > 8 bits
However, in some cases 8 bits i.e. 256 values is too many, like we may only use less than 10 values. Therefore, a small-int (4 bits) type i.e. 16 values is helpful and can save some bandwidth.