I should probably qualify that this only applies in some circles.
You have to remember there's a lot of "facade" in applying for a job, unless you have exactly what your employer is looking for (in which case your interview was just a procedure, not a contest).
It may mean little now because most job interviews go beyond the facade, bells and whistles. At some point in time, having a non-Hotmail address looked better on the resume, as did, for those who could afford it, having your own domain email address.
All facetiousness (really?) aside, there's also a number of reasons I prefer Gmail over Microsoft Outlook online / Hotmail, let alone others like Yahoo! Mail.