I just looked at my IRC logs and it would seem that you're in #coreos on freenode, which is a channel which is exposed into Matrix as #freenode_#coreos:matrix.org (thanks to folks like M-hash accessing the channel over Matrix). Whilst you may not have directly communicated with M-hash there, it does mean that you are (very) indirectly utilising Matrix already to communicate with folks.
However, both Hangouts and IRC are obviously not end-to-end encrypted (unless you layer it on top). So if you want the convenience of communicating to bridged users, you necessarily end up exposing plaintext and metadata at the gateway. So I guess this is a scenario where the tryptic of convenience/security/freedom breaks down at the expense of security. I'd still argue that one can still achieve security in a Matrix world without significantly compromising convenience by saying "hey, M-hash, any chance you can use an E2E capable client (e.g. a native matrix client like Vector or WeeChat, or a (currently) hypothetical axolotl-compatible 3rd party client like Signal, WhatsApp, Wire etc should they ever be bridged into Matrix.). You'd then continue the conversation in an encrypted room, and achieve the trifecta :)
In terms of Hangouts: nobody's written a hangouts bridge for Matrix yet; i'm not sure why as it'd be trivial to take one of the 3rd party libraries and hook it up. We're still quite early on in the process of building out bridges ourselves, but contribs from anyone reading this would be enormously welcome!
Re: Yes, you can pick all three, and you can do it right now.
However, both Hangouts and IRC are obviously not end-to-end encrypted (unless you layer it on top). So if you want the convenience of communicating to bridged users, you necessarily end up exposing plaintext and metadata at the gateway. So I guess this is a scenario where the tryptic of convenience/security/freedom breaks down at the expense of security. I'd still argue that one can still achieve security in a Matrix world without significantly compromising convenience by saying "hey, M-hash, any chance you can use an E2E capable client (e.g. a native matrix client like Vector or WeeChat, or a (currently) hypothetical axolotl-compatible 3rd party client like Signal, WhatsApp, Wire etc should they ever be bridged into Matrix.). You'd then continue the conversation in an encrypted room, and achieve the trifecta :)
In terms of Hangouts: nobody's written a hangouts bridge for Matrix yet; i'm not sure why as it'd be trivial to take one of the 3rd party libraries and hook it up. We're still quite early on in the process of building out bridges ourselves, but contribs from anyone reading this would be enormously welcome!