You should never run a car or motorbike tubeless tyre with a tube in for other than as an emergency short term repair. Never having had a tubeless cycle tyre or examined one I can't comment on their use, but both car & motorcycles have ridges on the inside of the tyre from the manufacturing process, these will eventually rub their way through an inner tube which will result in an immediate failure.
Interesting.
As
@DCBassman says, we used to put a tube in a tubeless tyre quite often in the 1970s.
I fitted lots of tubeless and tubed tyres in those days, and I don't recall the inside of the tyre being any different - not that I ever did a close comparison.
Things move on, at that time tubeless was an innovation not specified by many manufacturers, rather like the position with bicycles today.
I recall a few years ago asking a tyre shop about putting a tube into a punctured car tyre and they told me they no longer do it.
Tempting to think it's mostly to sell more tyres, but maybe there is now a valid safety reason.