To be fair Tritium's half-life is significantly less than radium. You really don't want to be breathing any radium dust if you can at all avoid it, which is a good reason we stopped putting it in things. But if it's in a sealed container (like a watch that isn't smashed/cracked up) surrounded by a few millimeters of material it's not going to be a big deal even if it's on your wrist for years.