Prefer them over patches? - no way! The patches are the real deal and showcase the artwork much better. The patches really hold a lot of meaning for my kids. You could ask them about a physical patch they have earned and watch as their demeanor changes and they talk about the projects they did to completed challenges for that patch.
A sticker does not have the same reaction and is not an heirloom ... but it's something. The events at our library based maker club are free - library policy. We have limited funds to work with, thus for us it comes down to having to choose between purchasing supplies, even as simple as duct tape, or patches. The supplies are a need to have, where the patches are a would love to have.
It's not a knock on diy at all. I think the patches are priced right. It's more of an issue of funding and helping others see the value in making, so future support is increased.