I believe they had a big backlog that was originally mobile-only, so that made it easy to dump a whole ton of them on traditional handhelds and consoles in a short span. They also have multiple developers making them.
I bought the two that were released on PSP and all of the ones that got physical releases on Vita. I haven't finished all the ones I've bought thus far, but if I ever get through them all, I'd be up for buying more, probably the digital-only ones on Vita. But when I buy them digitally, I try to get them on sale. I think I got the PSP ones (End of Serenity and Mystic Chronicles) for around $5 each, and I definitely got at least 5 bucks of worth of entertainment out of End of Serenity (simple, breezy RPG that took me around 15 hours to beat, if I remember correctly). I was actually thinking this past week that I'd like to start up Mystic Chronicles.