Most of the time wacthes become more valuable when they are out of production.When people cant buy them easy the interest gets bigger and with the interestst getting bigger the price goes on. Its not only rolex watches that can be used as an investment , most of the luxory watches can
This applies to designer watches or those that really are branded and expensive watches. You're right that it's not just for rolex and there are also other brands that are expensive and can be more expensive in the future if those models are no longer manufactured.
Still not fond of the investments through luxury watches but I'm keeping an eye on it.