Watch ratings are NOT similar to dive computer depth ratings.
Watch 30m = minimal rating, not water-resistant.
Dress watches, for the same situations where you'd wear a suit. Ranges from essentially no WR to safe for showers when new. Unless you're sure, limit water exposure to washing your hands, but only wipe the watch itself with a wet towel.
Watch 50m = some water resistance. Usually safe to gently wash the watch, unless the seals have aged.
Watch 100m = actual water resistance. Safe for warm (not hot or contrast) showers. Implies that it can be worn while swimming. Good non-chronograph ones usually can, if they've been serviced regularly and the crown is screwed tight. With most swimming should still be avoided, because aging of the seals or touching any buttons in the water will cause leakage.
Watch 200m+ = dive capable. Can actually be taken to a significant fraction of their rated depth if tightened and with new seals. 100m->200m is the biggest jump, except for the few older 100m models that were more honest in their rating (and serviced!)
I killed a 200m watch once by not re-tightening the crown before swimming (not diving). It felt tight, but there was a last quarter-turn where it would feel that way. Don't be me.