What are the limitations of blueprints? Are they for only First Person Shooters or can they work on every Genre including RPGs?
They can be used to make any game. The only limitation of Blueprints is their lack of exposed functionality. Some engine functions, few in number and usually a bit special, are not bound to any BP node so you would have to reimplement the function OR create a C++ class that interfaces between BPs and these missing C++ functions.
Other than these few rarely used functions you have everything you would ever need to make any game.
HTH
^ and you should maybe check out Sjoerd’s videos on how he did things in The Solus Project. Nearly the complete game is made with Blueprints.