I would not say that it's been a complete waste of money. For instance, I do use the new table function in DP20 quite a lot. I prefer DP20’s tables than DPX19’s tables.

Also, no nag dialogue when the (now non existent) update service expires. With 19, I had to add a firewall rule to stop it (after figuring out which IP to block DPX19 from accessing).

Note: I never really made use of any of the templates from earlier versions, and yes, I do use the clip art from earlier versions that I wanted.

I guess with Xara DP20 (or any software really) YMWV