One of the reasons that the LSLs were "restricted" when wishing to do a beaching was due to their "civilian" status and registration.
The beaurocratic mind-set dictated that a beaching (even a well controlled one) was, in effect, a "stranding" or "grounding" and so the ship involved should be subject to a survey. Absolute clap-trap really, as that was what the ships were designed to do in the first place.
I last drove an LSL "up the beach" just south of Tromso...but we didn't tell everybody. But at least that was done on purpose, and only a few days after one of our "through-deck-cruisers" had done the same thing (inadvertently) only a few miles north of us. But as the Grey Funnel Line is not insured in the normal way only the tax payer was charged for repairs.
The LSLs were absolutely the right size for this kind of operation. With one drawback. Obviously one wouldn't choose an area strewn with rocks to plonk a biggish ship down on, so a sandy or shale area with gentle declivity was needed...and the ship trimmed accordingly. Just tough luck if the "invasion" was to be on a coast with cliffs and/or rocks...you'd lose the ship. But the "drawback" I mentioned was something entirely different. Run up the "beach", and then open the bow doors. The bow doors then pushed all the sand/shale aside and the resulting hole was then filled with water. Oh, how we laughed when the more "gung-ho" types decided to be the first on to the beach. The extendable ramps filled the gap..but I guess it was a bit slow if it was in a real fire fight. Much easier and better for the vehicles to be discharged when the beach had been secured.
LSLs were basically a very large raft with massive buoyancy and ability to absorb punishment, but with the addition of a lot of "stuff" on top to make them look like a real ship (and to make life bearable for those on board). Ocean going trucks, and quite wonderful to drive.
But times change. The new ships are much larger and more valuable than the LSLs, nor do they need to beach. An LSL would beach at around 4 knots, loads of time for an "enemy" to target it.
The word "amphibious" when referring to a ship is really a mis-nomer. They are not frogs or toads. It really just means that they can conduct operations on both land and sea.....or at least, the forces on board can.