Usefulness is moot. You can tell what it is. When most ships are below half, they'll fold up pretty quick. Think probably the Fish and maybe the Galleon are the only two you really don't need to go "oh shit" about.
Squid = Well, no more ramming. Okay maybe ram only when they are ultra weak.
Pyra = Holy crap that is what 50% hp looks like! Hey guys look, 50% hp!! I'm not dead!! Quick someone take a screenshot!!
Junker = Meh, just keep the balloon and engines up. As long as we don't get popped and stomped, we'll be fine.
Spire = Hey Billy Bob, more hammerin, less shootin this time!
Mobula = SIT ON THE HULL!! I DON'T CARE IF ITS ALL QUIET!! SIT ON IT!! YOU WILL SIT THERE AND STARE AT IT TILL YOU FIND THAT HULL SEXUALLY ATTRACTIVE!!!