The bezel is also intended to be used to measure approximate bottom time, rather than just decompression time. This is the reason why the bezel markers go all the way up to 60 minutes.
You can do that on watches that have a countdown bezel (like the Sinn EZM1), but you can't do that on the Cousteau, Sub or SD etc (which only measure elapsed time and have no minute markers beyond 15).
This is all rather academic anyway, as divers watches have long since been superseded by dive computers as the device of choice. In fact someone was telling me recently that the bezel on a gen IWC divers watch (I can't remember which model) does not rotate below 10 meters. Whether this is deliberate or not, it means that you cannot use it for deep safety stops.
Offshore is absolutely right about needing a good working knowledge of decompression limits regardless of what equipment you use, although I would add that the bare essential knowledge is taught as part of the minimum qualification requirements for recreational divers (e.g. for PADI or BSAC qualifications).
I use a Suunto D6 dive computer, which cost around US$560, although very good computers can be had for much less than that. I personally would never want to dive again without a dive computer and every other diver I have spoken to who uses one says exactly the same thing. As an indication of how important dive computers are seen to be, PADI will not let you obtain the advanced certification unless you have one.
ps. Offshore sorry to hear about your necrosis, it's a real shame that you had to give up diving.