I can't believe you just said speed isn't useful.
Sorry, to clarify, speed in and of itself is quite useful, in fact it is arguably THE power stat of the game (part of the reason high tech ships seem to outdo low and mid tech ships, thus balancing and additions in the next patch). But the additional speed added by the SO zero flux boost (on top of normal SO speed boost) always being available is essentially neutered balanced by a crushing loss in PPT. So deploying an SO ship early in the battle is kinda pointless, as it will likely run out of PPT before generally being useful (put another way, seems like the only real reason to deploy a SO ship at the start of a battle is to try to quickly capture a strategic point and maybe bog down the enemy for a bit, but then you'll have to quickly retreat the SO ship or have it risk having CR go to 0% and the ship prolly die).
Hence why it seems adding the zero-flux speed at any time to SO was primarily intended for Hyperion and nothing else (although yes, other ships would still literally benefit from it, but only Hyperion can teleport across map to a retreatable position).
Edit: spelling, but also forgot to add this:
It also gives the engines their brightness helping signify to the player that the ship is using SO (alongside the color change).
Zero flux speed boost in general gives a different/longer drive plume, SO plume change just adds mostly more flavor/color (although also needed for a player to know if an enemy ship has SO hull mod during battle).
I think you're overestimating the cut in PPT. PPT doesn't tick down unless the ship has enemy ships in sight. The drain after PPT is over is still the same so effects that reduce that drain drastically increase the time the ship can stay in combat. Stacking hardened subsytems with reliability engineering nearly doubles that time just from the drain reduction. Reliability engineering gives 15% more CR, nearly doubling the time again until malfunctions. Then there is crew training for another 15%. Ships lose .25% cr per second after PPT is gone. With all that above, the SO ship can avoid malfunctions for 6 minutes AFTER PPT is over and you should be able to get a few minutes of PPT as well. Plenty of time for it to have a significant impact on the fight.
It will last even longer if you micro it a little. I like to put SO on already fast cruiser (aurora, fury, falcon, even eagle and champion will work) and then use it to bully enemy frigates trying to take points. Frigates don't trigger PPT drain for cruisers so the ship can do this forever. Once the enemy is out of frigates, they start sending destroyers and cruisers but the SO cruiser by design excels at 1v1. This all leads to the enemy's ship line becoming smaller and smaller as they trickle ships trying to take points.
SO ships need that speed boost not just to get to fights, they also need it to get in and out of enemy ranges so they can dissipate or to flank vulnerable enemies easily. Without it, they will get fluxed out before even getting in range of the enemy. It also gives them a bit of a weakness like I said before. If they get overloaded, they lose the 0 flux boost, preventing them from easily escaping.
