I had a long wait on their chat bot and had a bunch of time to play around, and, indeed, the app seems to work better than the website.

I, too, could find no way to add a companion to a reservation on the website. But, on the app (at least on the ipad app) the primary member and all the companions are select-able buttons above pax 1, pax 2, etc, as well as above the contact info fields.

Also, playing around, I find no way to 'delete' the cart on the website. But, the app allows you to arrow back to the beginning which appears to wipe the cart.

Also, it seems that half the time that I fill in my search on the website, it sends me to another slightly different screen to input the search again. The app does not do that.