I am curious what makes class B shares interesting  vs. class C shares?

Using CAIBX as an example,  AF;s website lists the net E/R of the B-class as 1.32.% Class C is 1.37%.    Really, who is going to miss 5 basis points of return?

The CDSC for the C-shares will not be levied after 1 year vs. the multi-year drawdown of the CSCS on the B-shares.

What am I missing?