As with anything, done for the right reasons is fine, done for the wrong reasons is not. Personally, I don’t wear it but then I’m one of the Irish/German/English Catholics. Not much hispanic there. :p
I have thought about it but I think a good divide is this. Would you wear it around the neck but under the shirt? If the answer is yes, then it’s for the right reasons. If not, then you’ve got your answer right there. I know a very good friend of mine who does so, but no one would ever know, unless they thought to ask.
good point — if it is not “for show”, it is something close to your heart