In my view, the Credant purchase should be set in the context of Dell's manouevering in between Intel and MS.
Dell clearly decided a few years ago it wanted to deliver a security service. Credant was a part of that service for many moons. They have merely brought the expertise in house. I assume the price was right.
I don't see Dell buying Credant to get into Wave's space. It costs more to make Wave's software (note balance sheet) than to buy the company.