~They don’t seem efficient enough for commercial use, just military use.~
Or probably just the opposite. For military it is a large blinking target. Look at it as a hybrid of a boat and an airplane. Ekranoplane takes much heavier payload than airplane is ever capable to lift and it is almost as fast of that same horsepower. If you need to move some heavy stuff across the ocean in hours, not days these things might be useful. On the other hand I really doubt if they are able to negotiate bad weather.
Jet turbines are terribly inefficient at sea level. Better convert them to run on Ukie natural gas.
Ekranoplan was heavily supported by N.S. Khrushchev along with several others of his crackpot schemes. It was basis for Brezhnev & Kosygin bringing his removal from power in 1964. No more Nikita, no more funding Ekranoplan. Dead letter by 1967 or so.
A seaborne supersled is easy aerial target. Maybe Caspian Sea ferryboat, OK for that because no more Aralskii Morye.
“On the other hand I really doubt if they are able to negotiate bad weather”
Probably not. But they can sit until the squall is gone, then fly the route and still arrive faster than the ship that chugged along thru the storm. For inland seas, these things are pretty good on fast freight.
A ship defeats them on tonnage it can carry. People never really appreciate how small airlift actually is alongside sealift.