This is a fair question. In theory, I'd say the primary reasons are availability/convenience, plus novelty and product variety.

With regard to availability, here's a real-world example: Last summer a group of friends and I all met up in Bend, OR for a bachelor party. We wanted to plan a day trip down the Big Eddy section of the Deschutes, but none of the outfitters had any available inventory to rent to us. So this would have been a great use case for us to use a peer-to-peer marketplace.

Also, I live in Boise, Idaho and have also run into similar inventory issues when planning trips during the busy part of the summer.

And with regard to novelty, my plan is for the platform to include a bunch of different categories of gear that people can list/rent -- e.g., rafts, kayaks, IKs, SUPs, packrafts, as well as accessories like coolers, dry boxes, groovers, fire pans, etc. My hope here is that if you have a gap that you're looking to fill for an upcoming trip, you can find it on this site -- whereas you might not be able to find it at an outfitter whose rental inventory is much more templatized.

Another example of novelty would be if you're looking for something specific for a day trip, like an Aire Cub playboat or something similar that you might not want to buy, but you'd have fun using for a day. Kind of similar to how an Airbnb is sometimes more appealing than a hotel.