I've done 31 locationless caches, although none for a while. Like Ullium, I first thought that they were a bit too effortless, and some certainly are. However, many are pretty challenging.
Like others, I think that they should be categorised and counted in a different way -not unlike trigpointing. In a sense they are like cache hiding where you search for a location first, then log it's co-ords then get it online.
I'm unhappy that the 31 locationless caches I've done are included in my total, and I always mentally discount them.
Having said that, if we go back to first principles, and accept that geocaching is all about getting out into the landscape and getting your eyes opened to places you wouldn't normally see, then locationless caches certainly fit the bill. (Pun fully intended Ullium!!)
One of my favourites was Fading Ads and I still look for ghosts on walls gable ends wherever I go.