The exchanges such as Poloniex will trade SAFEcoin, they have even asked when the swap from MAID to SAFEcoin will occur
Because it is not part of the SAFE project, but one of the first Applications to start development for the SAFE network. Important difference. safex is a different project to the SAFE network project, the same as safepress is yet another different project.
You may wish to read more on that subject
And a thread on SAFEX
https://forum.autonomi.community/t/safe-exchange-safex/1690