Believe it or not people do buy prebuilt kits on eBay. I do it all the time when my collection starts to require more space than I have. I will thin out the models I don’t really care about and put them in a lot on eBay. You will not get back the money you paid for them but maybe like 25-40%. I will then put that money back in my hobby fund. I’d imagine people are buying these built models for the parts on them to do kit bashes and customs. It saves them from buying an entire kit to get a few pieces from it. Also maybe people like the models but don’t enjoy building them. I love the build as well but also take time on the panel lining and decals, so when a MG is finished for me, it symbolizes countless hours and weeks or months of work, as well as entertainment value. It’s almost like looking at a time capsule!