I have always considered the idea of a
fundraiser to be excellent. But I think it's not easy to inspire trust in a product that doesn't exist yet, be it software, hardware or literature.
I believe (but maybe I'm wrong) that the most successful ones have had a good
marketing idea. Others perhaps started from a working prototype that gave the idea of the final product or they already have a pool of followers who would support that idea or those people because they already trust.
A second important point is what to have as a return to the donation. Some set donation thresholds, and based on them they will receive the final product, a discount or a simple letter of gratitude.
I personally believe that crowdfunding for an Application is the most complicated thing to do. Because the final product you never know if it meets the needs of those who supported it. Each developer has his own vision, and it is already difficult to match it with the customer, let alone with dozens (or hundreds) of other developers who have their own method and ideas.
Some time ago
@sfsameer made an attempt that looked like a fundraiser to develop products, but in the end there was always someone who felt that the final product was not complete or should be done differently.
For Software products, at the fundraiser I would say that it is better to publish the final product and sell it at a low price, but whoever buys it knows what product they are buying because they can already see it in all its parts.
For everything else, fundraising is an excellent solution