Something to consider here is an ongoing discussion in MB, what is and what is not a release and the exclusion of home-made releases. The question I have is this... is that content valuable for people today and in the future? YouTube will have some real content of value, but also some person filming himself jumping off of things. It would need to be determined what qualifies and it will be a grey area, just as a bootleg is in MB.
Sure. I use TMDB and TVDB with trakt.tv and Kodi. First, I need to say I am not at all tied to any of these services except as a user and editor and/or reporting data issues for admins to correct. Trakt.tv is a movie/tv scrobbling and history service. It keeps track of what movies and tv shows you have watched and will keep lists. Lists like a watch list, scary movies list, etc, any way you wish to collect. Kodi is a media player, a bit more elaborate than let's say VLC, but a media player none the less. I use Kodi with trakt.tv in that when I watch a movie on Kodi, it uses the Trakt API to tell Trakt I watched the movie and give it a user rating. That data is then stored on Trakt as well as internally to Kodi.
Hoping all that makes sense, generally speaking, Trakt uses TVDB and TMDB to get its data on the movies and shows it keeps record of. So if I watch "Movie A", it needs to be referenced in TMDB in order for Trakt to know what it is, so that when it is told I watched it, it knows what I watched. There is the need for a database with complete and correct information. TMDB does well with movies, and to use the terms I use as well as many othere, TVDB is used because there is nothing else to use. It may be flawed and many have complaints, but they have the most editors giving them the best overall content there is to use with an open API which is needed.
Another use for TVDB and TMDB is to create nfo files for movies and tv shows. Although nfo files were originally used for warez content, that extension has also been adopted to store metadata on video content. From that file, media players, such as Kodi, can read the file and populate the media player with the details of the file you have included in its library. In the generation of those nfo files, you need sources of data, and TVDB and TMDB are two common and top choices for that. In addition to Kodi pulling data for this purpose, I also use an external media manger called TinyMediaManager. TMM also pulls data in order to populate its meta data fields and TVDB and TMDB are again top options there.
So in summary, the initial need that I was looking to satisfy is a replacement for TVDB at a minimum due to certain issues that exist there. Replacing TMDB was not a intention, but to replace 2 services with 1, that is just more efficient.
Please note that when I say replace, I am not looking to shut other services down. Replace meaning for my uses, and the many others that do the same, replace what I am currently using with a new source of data. This exact discussion has been started by many others in other places, so I know there is an interest in the above outlined usage.