It's such a rarely needed service that I can't imagine naming it AWS Data Center Mover would make any difference at all in terms of usage. The number of customers who could make use of this thing is tiny, it doesn't matter what it is called.

Those names assume a decent amount of technical understanding. A lot of times the people who will end up paying big bucks for these services don't know what transactional E-mail is, so calling it SES or Amazon Transaction E-mail wouldn't make a difference. So, they go with a "cool" name.

mbeaty_1 above me has a point, but I think Snowmobile & Snowball both tie into the naming for AWS Glacier.