As others have said, Kickstarter isn't a store...nothing there is for sale, per se. As you have noticed, it's a terrible place to buy stuff...mostly because there isn't much "stuff" to "buy." However, it's an excellent place to donate money to help fund creative projects because Kickstarter's policies help prevent rampant abuse, and some creators might even give little (emphasis on "little") rewards for donating. Usually these rewards are non-tangible, like a nod or mention in the credits. Sometimes it's a copy of the work, or rarely, a little collectible trinket or something.
But to your original post about whether or not Kickstarter was the right way to do this?
It sounds like Travis and Sam met with "dozens" of Hollywood executives and pitched the idea to them. For whatever reason, didn't like the offers they got. If I had to guess, these studios either thought it was too risky to take on the initial $750K investment, or they wanted to leverage more creative control over the final cartoon than Critical Role was comfortable with. So to get funding AND maintain creative control over their project, they turned to crowdfunding. And if you are looking for crowdfunding, Kickstarter is the largest platform on the Internet.
Whether or not this was the "right way" to go about it, only time will tell. I think the Kickstarter's current backing level speaks for itself.
Shameless plug: if you are looking for a place to buy dice, t-shirts, stuffed animals, and other Critical Role swag, don't go to Kickstarter. They have their own
online store for that...check it out!