Recently I mounted a CD image of LiT to play with SVM. The engine recognised the game, but popped a warning that running directly from the CD is not supported and it is suggested to rip the game and play from the HD.
Nonetheless i played and finished all the game without any problems (other than a graphic glitch which I remember was also in DOSbox). So I thought like reporting to the devs that it can be completable without ripping. I don't know what the possible problems were implied in the warning but perhaps it should be removed.
I think the problem with running from a CD is the time it takes to access data from a CD drive which could cause stuttering in audio and video or freezing while accessing data. That isn't an issue if you are mounting a CD image from the hard drive.
If I'm not mistaken, I believe this was mainly an issue with SCUMM games only back in the day because of the way SCUMM games work....if I'm not mistaken. Of course, if it were they'd probably have removed the message for other games. Unless they just didn't bother to remove it.