Lecht
You can sleep upstairs in winter with a topper. You can also get v expensive brandrup thermo liner for the inside of the roof that stays in place all the time.
The bed downstairs in the se is perfectly good for sleeping on and quite wide and long. We slept on our t4 rock and roll bed for 5 yrs when camping/ travelling and that was fine. The Cali bed is longer and wider.
You cant get the kettle on so easily in the morning in a beach!
I guess for me, the beach is about a simple overnighter after a bike ride or a surf trip etc, bit of a weekender van. The se is more about exploring, staying away longer and being self sufficent etc. I’d spend a week in the se in the alps skiing but wouldn’t want to spend a week in the beach in the alps for example. You can live in a Cali se but the beach is more like spending the night on your mates couch after a night out.