I guess that works very similar to any purchase you could make in life. You don't get infinite utility for infinite money, point being its not possible you can derive more utility by spending more money forever.

So after a while the utility is things like social status and wealth signaling.

Apply this to things like buying a car, or a home and it makes a whole lot of sense. If you need that expensive carpet just to show off while a cheaper one could keep your feet equally warm, then at that point in time you are spending for status and wealth, not utility.

In case of a watch, can your phone tell time? If so you are all set.