A classic cookie fundraiser in particular just like a classic candy fundraiser or classic candle fundraiser can be a great way for your group to raise the money it needs, without having to worry about whether your product will have a market or not. After all, there are very few people out there who don't like freshly baked cookies, and with a classic cookie fundraiser, your team does not have to worry about a hard sell approach.
People make them for themselves and their families, to entertain friends, or even to give away as gifts. A cookie fundraiser is also a good way to focus the attention on your group. If you do something really out-there or unusual, people might remember that, rather than remembering who you are and what you're raising money for.
If your fundraising is going to be a yearly thing, as it is with so many groups, then you want your supporters to remember your group first and foremost. A cookie fundraiser is something you can do year after year, and people will associate your name with the cookies they look forward to every time.