@ djvj -
If I recall there were more changes made to MESS post TinyCDi...mpeg support I believe was added.
How well ether emulate the CD-i I don't know...however CDIemu has a time limit per session, unless you bought it...hence why I suggest the other two emu's.
I think the main issue back when TinyCDi rolled out was that most games were in CDI image format and CHDman didn't support CDI at that time...so you had to load the images up in a VCD, then re-rip them to BIN...at which point you could then feed the image to CHDman and all was well. However newer versions of CHDman support CDI...however the new CHD version wouldn't be supported by TinyCDi...but would be with the latest MESS.
Yeah ease of use...is probably from not having thousands of options to over whelm the end user...but I never got around to giving it a good shake.
@ brolly -
You may very well be correct...but there is the session time limit to consider...unless you own CDIemu...then the discussion is moot.