Most rare, collectable kits are not very good models any more. With this in mind, it would be better selling it to a collector and using the money to buy an up-to-date model.
I sold a vintage Tamiay 1:50 scale Crusader tank for some serious money (like $200+). I used that money to buy the brand new Tamiya 1:48 scale Crusader tank kit for $25. The original Tamiya kit cost me around $5-10 way back when.
Some highly collectable kits are up-to-date kits. Like Dragon's Tiger 1 initial 3 in 1 kit. If you are a Tiger fan and just have to build this variant, go ahead and build the kit. If you just like tigers and any one will do, sell it and use the money to buy a different, less valuable Tiger to build.