I'm the chief mechanic at a large beach bike rental company on Hilton Head Island. For the beach, they are perfect for casual riders to get around. For those that need basic transportation, a comfort or hybrid bike is better. Road bikes and fixies are almost overkill.
I've got two cruisers for myself. One is a Fuji Shakalaka, but stripped of the fluff: no fenders or bags. The other started life as a Jesse James chopper bike, those sold by Huffy in big box stores about 6 years ago. I again lost the fenders, painted the frame gloss black, swapped in a long seat post, then different handlebars. For the coup de grace, I installed a 26" front wheel.