They rot and lots of people will have crashed them, so they'll get rare. OTOH, they're not particularly great AFAIK. Nowhere near as much as a mint MK1 or 2 GTi would go for (90 spec 16Vs go for £3K in mint condition), and lots more of them actually still exist. The fact that they probably drive like shit is going to stop a lot of people buying them as usable classics, and nobody's going to buy one to put in the garage and look at...