Aside from requiring everyone to install a plugin to do OTR, the crypto behind Matrix's Olm (based on Signal's Axolotl) is much better suited to asynchronus communication than OTR (and MegaOlm actually supports group chats).
There are many more benefits to Matrix, but just making clear that Matrix's end-to-end crypto is better than just plain OTR.
There are many more benefits to Matrix, but just making clear that Matrix's end-to-end crypto is better than just plain OTR.