I think the answer to your question "what do we get for registration ?" is in the long term, permission from the employer to open up medical devices & work inside them.
For far too many years the qualification for rummaging around inside medical equipment was a set of screwdrivers and the ability to deny everything convincingly if something went horribly wrong.
Groups of staff would fiddle with equipment and keep no records whatever. If asked where their records were they would simply ask "Why keep records?"
Over the years I have met some seriously frightening individuals who have opened up equipment and done the most stupid things simply because (a) they had the tools and (b) nobody in the hospital had the power to prevent them.
Many years back I had an attempt at stopping a group of unqualified staff from doing what they flatteringly referred to as "maintenance", only to have a senior clinician come down on me very hard. My line manager got scared and asked me to knock it off.
Some trusts have good equipment management and have had it for several years, some still don't. The essential thing will hopefully be that if you aren't registered you aren't allowed. In other words you will need to have evidence of competency (on paper)in the relevant area of medical technology to practice.
Go onto any ward and ask a senior nurse if you can borrow a screwdriver for a few minutes. You may be surprised at the number of tools that appear. Then go back and ask for a syringe and some drugs and watch their response. See what I mean?
For a middle aged tech like me registration is of course a bit worrying. My ancient City & Guilds certificates and a lack of any Physicist to support me may end up ruining my career, but I really do think the poor old NHS needs to get proper controls on who's allowed to do what.