The low pass is useful in certain scenarios, i.e. breaking the lockdown, if someone over extends their legs in butterfly guard. There's more, i wish we were on the mats so i didnt have to try explaining in words.
Anyway, I don't think it's about easy or hard, or preference for that matter. It's just what pass will work in what particular scenario.
Keep working on ur low pass, it'll be harder for ur opponent to be offensive with his guard if ur constantly pushing him with different passes.