Most beginners (especially kids) become proficient throwing forehand more quickly than backhand because it's more of a natural throwing motion.
That said, there are very few players at the top levels who are forehand dominant (Sarah Hokom and Sarah Stanhope on the women's side, Jeremy Koling and Geoff Bennett on the men's, to name a few). But all of them can air it out BH when circumstances dictate.
As Itchy says, it's best to be able to do both. There are times when a BH anhyzer will be a more prudent choice than a FH hyzer, and times when a FH anhyzer will be more prudent than a BH hyzer, such as a dogleg with the basket sits on the side of a hill that falls away beyond the basket or there's OB or a steep drop-off just beyond the basket, where an anhyzer will be stalling in and flexing back away from the direction slope/OB/drop-off, while a hyzer will be gliding in in the direction of the slope/OB/drop-off, increasing the risk of a skip away. Conversely, there are times when the skip will be advantageous. If you can throw both BH and FH, you have options when faced with those situations; if you can only throw one or the other, you don't.