They're kidding, oblisk. Fallout: Brotherhood of Steel is a true gem. It's the only spin-off so far that stays completely true to the original setting. The reason it flopped and can now be found for a meagre $3.99 is because the developers didn't want to go FPS + RT combat like Bethesda. FOBOS stayed true to the isometric perspective and TB combat mechanics of the original games, scaring away most young, inexperienced gamers who just want dumbed down action and immersion. True Fallout fans, however, love FOBOS, but usually keep quiet about it because were Bethesda ever to find out how much we enjoyed FOBOS, they might just consider to make FOBOS 2 and we all know how that would turn out, don't we?
I'd buy it if I were you. $3.99 is nothing compared to the amounts of joy you'll experience playing it. The game also features a magnificent soundtrack that'll remind you of the original games. So is it considered canon? You betcha. Where Tactics failed, FOBOS succeeded. That alone makes it worth whatever price is being asked for it.
A must buy, I'd say. Trust me.