It is a script languaje. Yo can make a gui very very easy, I have no idea, but can freebasic use the autoit dll to make gui....
a why should we care it a scripting lang and as far as i can tell it not like LUA were you can use it with FB as a scriptor for you program.
There are a few problems with it.. it's for Windows only, it's not under LGPL and figuring out how the interal gfx lib works would take more time than coding a full one for FB in C (it's matter of time).