If you can afford them, buy what you wan, and do what makes you happy. Life is too short.
Personally, I am not in the financial position to be purchasing those rare kits, but I do not have any problem with anyone who can afford to buy one. I have quite a collection, but I have come to the realization that I will not be able to build them all, so I am selling a lot of them off. There are a few that I will not sell, as I am definitely going to build them. Sometimes I can find a resin re-pop,rebuild-able polystyrene car, or a forlorn promo, and those are my preferences.
People who know me know I like big '60's cars, as that is what I grew up with, and I love pickup trucks.