I'm pretty sure this is trolling. I worked in banking for a number of years and more recently in private equity, and my standard outfit is a Banana Republic suit (tailored for fit of course) and a Seiko 5 diver. Never been an issue in any setting, including client facing situations. It's a pretty unmemorable outfits, which is its strength. I've of course encountered the odd colleague or client who wears a Patek or a Brioni suit to a meeting, but that is certainly not the norm.
If this is in fact a serious post, I'd focus less on the brand of watch you wore to your interview, and more on honestly evaluating your appearance as a whole. Does you suit fit well? If it was hanging off of you, or fit in some ridiculous hipster skin tight way, then that could have been an issue. Did you wear some ridiculous skinny tie from Urban Outfitters, or did you suit have a loud pinstripe? Since you mentioned your watch, was there anything especially gaudy about it (most Seikos are conservative, but there are a few styles that look ill considered)? Was your personal hygiene up to snuff? These are all superficial things, but the research show that interviewer tend to form the majority of their opinion on a candidate in the first 45 seconds of an in person interview, so worth paying at least some attention to for next time.
Of course, what the recruiter told you could all just be cover for the fact that the interviewer just didn't like you. Most of the time the decision between equally qualified candidates is not made for any concrete reason and is just based on the interviewers gut feeling. The recruiter then makes up some reason when the interviewee asks for feedback. That said, pretty sure HR and legal would frown on any feedback more specific than, "we didn't feel you were a good fit."