If you've only been there for a few months, how do you even know that the task is of questionable value? I'd take it as a very bad sign if someone who's still relatively new to the team thinks they know better than people who've been doing this stuff for years. Trust that your teammates know what they're doing, and if they really truly don't (which is possible), find a better team.

It took me around two years in to start feeling comfortable setting direction and priorities at a team-wide level. Of course, I was making my opinion heard long before that, but it was just that, an opinion.

At only a few months in you're still an unproven quantity. Don't expect to be getting the most important projects just yet. Take whatever you are given and knock it out of the park.