Don't fear: They use the open source SteemConnect tool, developed from the Busy.org makers. It is endorsed by Steemit.com and handles all your keys without giving them actually to the third party applications like Utopian, Busy or DTube. And besides, Utopian has 4 Million STeem Power delegated to big chunks from Steemit as well. So it is a very trustworthy project handled by capable developers. :)