They did a fantastic job, saved tons of money and probably have no debt. They have a safe, warm/cool place to hang out on the road which most people can't even imagine owning.
As for safety, the rv industry is highly unregulated. That's why there is so much junk hanging around on rv lots not to mention the fact that I have never seen a video of a school bus conversion that has caught on fire like all the other rv videos showing burning rvs.
I congratulate the people who did something out of the box, on their own and didn't get charged 300K for a bus with furniture.