Yes, the tires act like a keel providing sideforce. The front wheel also acts like a rudder, controlled by foot pedals. The left/right is inverse of an airplane rudder.
I don't know the angle in degrees, but it felt like it could be very close to the wind. The wheels resist sideways from zero speed, unlike a keel that needs some flow moving to be effective. Also the carts have very little mass compared to a boat. Those things together make the acceleration really exciting.
And sitting so low to the ground amps up the feeling of speed.
I was sailing in the Mojave Desert when it was about 40-45°C. The lakebed dust gets into everything and never really washes out. So it's a thrill to sail, but not as pleasant as being on the water.
I've always wondered how big could these get? Like could we have a jib staysail or mizzenmast? Most of the ones I've seen look like larger wind surfers in gokarts. Is there something similar to flying a hull like with beachcat sailing? Looks like a blast that I would love to try someday.
Well, I've heard stories of landsailing wagons in ancient China carrying dozens of passengers, but it's not something I've gone looking for history about.
There are also ice sailers that run on blades, but I've only ever seen 1 and 2 person "sleds" for that.
I think the size limit just comes down to the practicality, not the sailing mechanics. There are only a few areas with smooth flat land or ice, and mostly they aren't large. Not like water lakes and oceans.
I would love to see a great landsailing race across a big desert take off as a sport. There would have to be aid stations set up along the way and a decent amount of fast response medical aid though.
Having tipped over the tricycle carts like the Manta in the photo, I can say there's probably some upper limit to what I can righten without a crane.
The land must be very flat and smooth for landsailing, so I've only ever seen it on dry lakebeds. I don't think most deserts are navigable, except in basin areas where the lakebeds form.