Hmmmmmmmm............. I've been thinking about this. Is it expensive? It is more than normal tenor Ukes yes, but if I bought a solid one of those (rather than ply) and then added the machines and a pick-up and paid someone to do that (because I certainly could not) it would be pretty close to the same price, but without the resale of the actual kosher model. We all know that you can mod something as much as you like, but the re-sale is never going to keep up with the extra money you have put in.
Is it a toy? When it is plugged in and has a decent buffering pre-amp in front of it? Totally not.
Is there a slight change in technique? Yes, it is a different instrument, I would not expect to pick up something which was so radically different in proportion and instantly be able to do everything I can do on a normal bass.