I've been hearing a lot of fanfare about Smart Plugs, much of it from smart people I respect. But strngely, they are still not listed in the NEC, by NEMA, or recommended by ABYC. Since only greater than 30A is acceptable for shore power, these are the only plugs you can use:
ABYC allows a few more, through you will never see the 4-pin and the 20A cannot be used for shore power.
One reason, of course, is compatibility. A mix at marinas would be a further mess and require more (sometimes dodgy) adapters.