Certificates are good, are directly job related, require no wasted effort on "electives", and can be a good adjunct in tandem with one of the tech degrees so many ex-USNs seem to accumulate nowadays,...
Beware of "padded" minimum requirements from your sponsor where sponsors are required,...
Be sure your relevant USN experience for the cert is relevant,...
just because you stood firewatch while somebody performed eddy current, UT, et al, does not translate into being skilled to perform, although you may be "nuke" enough to pass a test,...
it sucks to have your ass handed to you on your first CIVLANT pre-employment interview,...