In the latest updated TDA readme in 2017, there is no mention of "only" for mikumikudance. The line is a simple advice on what software that can use the file format PMX and that is mikumikudance. Further down in the readme is the rules, and there is no mention of "only" for mikumikudance.
The line on this wiki "Model data can be used only by the MikuMikuDance software". Should be "Model data can be used by the MikuMikuDance software". Even the readme.txt that has been put on the page has no mention of limitations of software use https://mikumikudance.fandom.com/wiki/Tda
TDA retweeted a link to a blog that says it's okay to use TDA styled models in VRchat and as Vtuber. https://twitter.com/narupajin/status/1000033716347879424
I don't think he would retweet and not say "this is not okay". Since he does not deny the statements in the blog, then use outside of mikumikudance is allowed.