Domestic coastal air defense idea?

[Mk38]

Aegis ashore stations scattered around with slightly over lapping coverage combined with literal VLS barges being towed around between them.

 

[totoro]

if you're going through the trouble of putting missiles on the water, why not include even more important component - radars? I mean, if it's for protection, radars need more protection than VLS wells.

Anyway, where needed, coastal defense can make sense. But generally it's far too expensive to be put everywhere - so usually it's only for a very few select places. Like, right now, to protect approaches to Guam.