Well, the free PvP gear (the recruit armor with the expertise bonus) you get at 50 is just a start, of course. You get warzone commendations for doing PvP and the daily and weekly that comes with it. I'd guess if you're still a fresh 50 with not a lot of endgame gear, PvP can be rough. I can't really comment on that, since I started PvPing after already having most of my Black Hole gear. What do you mean, by the way, purple gear being unusable?
Tionese Crystals were used for getting Tionese gear, but it became pretty much useless since everyone gets a free Tionese set now and Tionese vendors demand only Tionese comms, instead of comms and crystals.
About the space battles... I think that's normal. I pretty much only hear Mako myself during space fights.