I agree that bind_param is unneccessary in this case.

bind_param is neccessary when the DBI (or rather the underlying DBD) cannot determine the type of the argument and when the type matters.

eg when a value is NULL - (then the DBD has no clue as to what type it is), when the SV behind the value has both a string and a numeric value (it does matter for some drivers) etc.

The DBI caches the type of the column, so you only have to give the type once, in subsequent calls the type will be remmebered.

These situations are not common, but they do exist.
They are not as uncommon as the cases where finish is needed though :-)