Um, they sell lithium deep cycle batteries. The new DPs can get them, sometimes as an option as an option. I believe the Monaco fully electric (no propane) option provides Lipo
They cost about twice what those Optima Gel Cell batteries cost.
For about twice the lithium price you can buy Lifepo 4 batteries. They are much better. Lipo has a relatively short life span, by number of charges, not use. Like your cell phone, if you charge it even if it has a good charge, it won't last long. Life (lithium iron) batteries have a much longer life. More than twice the lithium.
This is all just from my memory of various magazine articles. Research it yourself, I wouldn't bet the house on my memory.