HC's are for the person who services his own equipment and will always do so. Sticking a car buyer with a HC system would be a cruel joke when it came time for them to get any service done. The same goes for refrigerant blends, but you're more likely to find a shop that could do the work.

Other than that, if you do your own work (or have a HC capable shop), I don't really see that it's a huge problem. Although I would adequately label the system (cover the old 134a label with one of them) and shrink-wrap the ports. That is, if it is legal in your state. And if you have a R12 conversion, you had better convert to 134a first, then be disappointed with the results. If you use a death kit, that's pretty much assured.