I kinda stopped reading when you said you were following twitch viewers of the game.

FFXIV is a fun game, but a very boring game to watch. I don't know why anyone would want to watch someone play an MMO. That's not a good way to tell how popular the game is.

Also of note, half of the effort they put into the expansion was the story. If you skipped the story, then yeah, SB is probably a waste of money for you so far.