Seaplanes are useful for flying to or from areas in which there are no runways (which after WWII became fewer and farther apart). They are unecomical in today's commercial markets, are in almost every case antiquated in design (and those designed with jet engines have been notable failures), are unsuitable for operations in windy weather or when "the surf's up", and have a safety record abysmal compared with conventional a/c.

They are great for fisdhing trips into the back country or short flights to nearby islands without airports, but I suspect the guy in Greece will soon be out of business.