The only difference is that in PvP, the higher-level content is mixed in with the lower-level content. So if you need better gear to do the higher-level content, then you can never do *any* content. (hence, PvP's current well-deserved reputation of being very newcomer unfriendly)
I also used to see people in pretty good gear doing sm KP and EV for the comms. And there's always ranked wzs for "higher level content".