Captain
Final Approach
Too much money for the speed ,and maintenance cost can get prohibitive,if you use them in salt water. They do however look cool.
I disagree, they do not look cool. Big pontoons strapped to a plane are not aesthetically pleasing. The goal of flying somewhere is usually to save time and that time is saved due to speed and aluminum canoes wielded to the plane tend to screw that up.
Granted, it opens up destinations otherwise inaccessible, and the time factor applies in those cases...but it's too few and far between so the market is small resulting is fast zippy planes being more desirable.