Well it's not the "only" way. It IS the only electronic way to change the ride height. You can do it mechanically if you make/buy custom suspension links. It's the same thing the Llams kit is doing, but you fool the sensor into thinking the suspension is at a different height, rather than tricking the computer into thinking the sensor is at a different height. Same concept, but ones mechanical, ones electronic.
Here's a link to a thread on it. Custom link thread
The thread was started by people who were lowering their Jeeps, but same concept applies in reverse to lift it. I did mine (see posts #208, and #237 for specifics). My Jeep sits at OR1 height, when the computer/sensors show me at Normal height. So for your beach situations you can be at any speed and the suspension stays at OR1 height. If you press the button to air up to OR1, it goes up to the actual height of OR2. The up side here is that now you can run up to 50 mph at OR2 height, instead of having it lower back to Normal when you hit 20 mph.
Here's a shot of mine in "Normal" mode. As noted it actually is at OR1, but the Jeep thinks this is 1" lower than it actually is so it displays Normal height and won't lower when I speed up.
And in case you're wondering, the tires are 255/70/18, which is 2" bigger than the OEM tires, but still narrow enough to fit the spare under the floor in the cargo area.