Newbie question About 3d and 2d

Hi guys; i have a stupid question. May be you can help me…

Last night i was making a hd clean; and i found my son has a lot of 2d and 3d (1080p) version of the same movie. And Some othher with 2d and 3d video track (1080p ) into the same mkv container.
So my question is..

if i download a 3d version of a movie and, in kodi, i play it in 2d with 2d stereoscopic option, technically, there is a lost of quality in image or something like this…?
AL 3d movies are in mkv, fullhd an 3d sbs, and 2d are in fullhd..
Thanx for your help and comments