Do you need double kick pedals?

You'll need a double pedal to make it work. It also has a lot to do with mental coordination. When your feet are working double-time, it's difficult to make your hands independent. So, you're going to be limited to some basic double-bass songs if you're working with a single bass and single pedal.

Are double bass pedals worth it?

So double bass pedals are crucial to your drumming for sure! But they can also suck up a lot of time when it comes to tweaking them so that you're able to play faster. If you're into that, that's fine. But be aware that it will cost you not only time; more features to tweak make for a higher price as well.