That "jetboat" is out of place in thus comparison. It's a much bigger and heavier and more expensive advanced combat vehicle, where as the others are purposefully designed to be cheap and basic. Realistically, you could buy like 30 of the others for the price of 1 "Daggershark".
Strange because in JC4 it acts like a patrol boat so why in God's name would the black hand spend money on something like that (or whoever makes it most likely prospero) when they could just use it to build a cheep a** boat that's very expendable
Because they want their equipment to be the best? Also, because the Sea Heist DLC introduced us to the idea that the Black Hand apparently have some kind of "jet boats" somewhere (tho that one was unarmed).
Triton G3 Taiphoon
YP-107 Phoenix 
Custode 29
daggershark jetboat
