Yeah, the game opens up a ton when you hit 50. It is in way, when the game truly begins. A significant amount of content sits behind that level 50 wall. The EX fights are even harder versions of the hard mode to put simply. They have new mechanics, stronger attacks, more HP and in general play very differently from the previous version while still having some similarities. They'll feel familiar, but you'll quickly see that's all it is familiar. They'll be totally new fights. Titan EX is still the stop gap for many people.

Coil unlocks after you complete all of the original Hard Mode Primals, Ifrit, Garuda and Titan. There is a quest that becomes available to unlock Coil at that point. Just do that and it is open for you to do.

It is surprising to see people just handing out gil. But he could be referring to getting crafted gear to tide you over until you get full myth/coil/soldiery gear. The more wealthy players will craft or buy the il70 gear and meld materia on to them. It will make them comparable to the myth gear. So some will do that until they have the myth to afford the rest. But yeah, gil will likely not be used to upgrade your jobs, but your crafting and gathering.