It works best when you have many references and few on-wrist photos. Watch stores often carry dozens of models and dial colors, and booking a hand model for each one is expensive, so usually only the bestsellers get on-wrist images.
With the AI watch try-on you can give every watch an on-wrist image and show it on different genders, ages and skin tones, with a suit cuff, a knit sleeve or a sporty scene.
When you upload a wrist photo, use only your own photo or one you have permission to use, never a public figure, and keep other watches and bracelets off that wrist.
If the photo already shows a watch, the model tries to replace it so only one remains, so check for leftover straps.
Before a result goes live, check four things in order: the dial text and hands, the case and bezel, the strap and buckle, and the hand itself.
If any of them is off, keep the watch photo loaded, pick another wrist or add a short note, and generate again. Dial macros, casebacks, case thickness and lume are still best shown in real photos.