Is it worthwhile getting them on a crap hybrid bike? Or is it for serious roadies only?
See plenty of cyclists riding hybrids using clipless shoes/pedals. For what it's worth, I switched to them last year after getting a new road bike. Took me a while to get used to them, and had a couple of 'moments', but they make a positive difference for me. As others have said, they help with the upstroke of the pedals but, and more importantly for me, once I got them set up correctly for me they keep my feet and legs in place whereas I tend to splay all over the show when getting tired on normal pedals.
My clipless moments, and most of those for others I've spoken to, tend to happen at slow speed and usually when getting little over confident (i.e. staying clipped in while weaving along the pavement until I finally fell in front of a large queue at the bus stop). I've got SPD pedals on my road bike and have the tension set fairly loose (plus mult-direction cleats) and they are easy to clip out of and I have never pulled out by accident. Also, a little spray of WD40 on the pedals keeps them nice and smooth when clipping out. Have been off the bike for a while and went for a test run up the road earlier to make sure I hadn't lost the knack before I ventured out into traffic and clipping in and out felt like second nature.