Tails can boot from USB. You don't need to not use Windows/OSX, you just need to boot into Tails prior to using PGP.
Is it inconvenient? Yes. Almost all privacy/security is. Security is largely a series of tradeoffs between privacy and convenience. The more privacy and security you desire - the less convenient everything is going to be.
Burner phones, faraday cages, encrypted harddrives, using cash/bitcoins (which should be purchased with cash), using a VPN over Tor (and not Tor over a VPN). Making sure any phone calls from different locations with none being near work/home, that the call is kept very short and preferably with a short and precise coded language. Cycling your PGP key frequently, and scheduling all electronic communications as to not give any hint of any "active hours".
All of those are inconvenient, but necessary, if privacy and security are desired.
Is it inconvenient? Yes. Almost all privacy/security is. Security is largely a series of tradeoffs between privacy and convenience. The more privacy and security you desire - the less convenient everything is going to be.
Burner phones, faraday cages, encrypted harddrives, using cash/bitcoins (which should be purchased with cash), using a VPN over Tor (and not Tor over a VPN). Making sure any phone calls from different locations with none being near work/home, that the call is kept very short and preferably with a short and precise coded language. Cycling your PGP key frequently, and scheduling all electronic communications as to not give any hint of any "active hours".
All of those are inconvenient, but necessary, if privacy and security are desired.