Welcome to the thread!
To answer your question, well... yes, sort of.
Brave Exvius is a new Final Fantasy game, in the style of the SNES titles (IV, V, VI). That said, the game plays considerably different from the SNES titles, outside of combat.
There is an original story with original characters. But, don't expect any literary masterpieces like in FF VI. The story is just enough to keep the game organized and not much more than that.
The game is belongs to a genre known as gacha, or lottery-style game. In this game, not only are there original characters, but the player also has the be ability to pull characters from other Final Fantasies (both heroes and villains) to join them on their team. This is a major draw of the game. On the flip side, as a lottery-style game, the more desirable or popular characters are often quite hard to obtain, and attempts at pulling for them cost a premium currency (lapis) in the game. A fair amount of lapis given to players over time for various events in the game (Brave Exvius is unusually generous in this regard compared to other games in this genre). Addiitional lapis can be purchased for real-world currency to fund additional activities in the game (refilling energy) or for more attempts at pulling rare units from the slot machine.
Various activities are also inserted into the game from time to time, that offer unique equipments, materia, spells, and so on that are not found in the story mode of the game. These can take the form of a dungeon from another Final Fantasy, an exploration of some kind, or a trial against a powerful boss (which is what everyone in the thread is passionate about at the moment as that is this week's challenge).
In this regard, you could think of this as a single-player MMO, as new content is constantly added to the game weekly and new chapters are being added to the story monthly.
If you want to give the game a try, the community would be more than glad to support you on the way. We are pretty passionate about helping GAF succeed here, each in our own ways.