Sounds like you know the answer already. The costs and risks of CCR are not worth it (imo) unless the type of diving you are doing would be more risky/expensive without it.
Check this out (if you haven't already), especially Pt.6!:
http://www.haynesmarine.co.uk/images/stories/A Survival Guide To Rebreather Diving Nov 2011.pdf
The risks of CCR are belaboured to death everywhere, but bear in mind that there are several ways that they make (at least some parts of) diving safer, even in pure OW recreational settings. Doing a swimthrough and you get tangled up? No need to worry about gas remaining, just lots of time to work the problem. Significantly longer bottom times while still remaining in NDL. Warm, moist gas reduces physical discomfort, reducing task distraction etc
Deciding to dive a rebreather is interesting and is at least 10x more likely to kill you than diving recreational SCUBA.
The 10x number really doesn't control for the type of diving people are doing on CCR, especially since the past and present paradigm is to only move on to CCR when you can no longer do the dives on OC. That means a lot of CCR dives are inherently dangerous regardless of the equipment used.
The vast majority are doing it for fun - not too different from buying a racing motor bike...
"Because I want to" is a totally valid reason to investigate a CCR, after all that is the same reason we are diving in the first place, mostly.
Cave divers are also more likely to have the self-discipline required of CCRs.
The self-discipline is the major aspect. You need to be thorough and conscientious about setup and pre-dive or a minor mistake can bite you hard. Complacency, with the current state of tech, is way more dangerous than it would be on OC. Depending on the unit you dive, though, there is not a huge amount of concentration required during the dive, more than what an attentive OC diver would display (solid state sensors and an eCCR vs a full mCCR with galvanic sensors, for example)
Never washed, never serviced, just pumped up and used then thrown back into the shed until the next weekend. Never let me down once. Try that with CCR and you’ll be another line on the excel list in very short order
I would argue that treating your OC tech gear that way is unfair on your teammates and, in some ways, is also likely to get you on a list, even if its just a "not diving with that guy" list. Dont get me wrong, I am not the worlds greatest maintainer of OC gear but it is worth mentioning.
Having a healthy respect for the hazards of CCR diving is of course one of the main prerequisites for diving them
Once you need helium for your dives, as per the OP, you are arguably beyond the point where a "casual" respect for the diving environment and your equipment is appropriate. Of course silent running is correct here, respect and cautious progression is the name of the game here.
In my opinion, if you aren’t OCD about the maintenance and setup of your equipment, you are probably well advised to have second thoughts about getting a CCR.
Yup. No shortcuts, especially on CCR.
I'm not scared of my rebreathers. Contrary to what you might read on the internet, they're not trying to kill you. They are trying to keep you alive.
That being said, complacency can and will kill you in a heartbeat given the opportunity. Don't deviate from the basic rules of diving a rebreather and you'll be fine.
This. Get trained well, internalise the procedures and checklist and adhere to them ALWAYS and you should have no problem having years of fun on your "life support system" on your back. Or side, but thats a different can of worms...