I am glad that reading through this thread the opinion goes from IT'S CRAP to it's pretty good!
Like every one else has said, kills are not your concern. Neither is the single line ink trail, because it is, imo, not useful on rollout at least.
I very quickly adopted a playstyle revolving around filling my special meter as quickly as possible. To do this, you want Special Charge Up. Other useful skills for this weapon are Special Saver, Ink Saver, Ink Rec, Ink Res. Ink Res is almost required imo for the times you have to roll across enemy ink.
On start, you immediately deviate from the team. With sprinkler, toss it into commonly uninked areas or other wise hard to ink/waste of time ink areas, like the left side of the crates on Walleye Warehouse. Then paint ink while hopping, refilling your tank just enough (you will be running quite low from the sprinkler throw). You should fill your special quickly this way. Upon emptying your tank, or after finding a safe place, shoot the Inkstrike into where the enemies are/important areas. You now have a full ink tank, and your team has in this time already reached important areas/mid/whatever. If the team shot an inkstrike behind you or something, you can toss a sprinkler into the center and rack up points. Otherwise you can advance and toss a sprinkler high up onto chokepoints or other obstacles, or keep advancing straight into enemy ink.
At this point you should be either advancing or defending, depending on map and current predicament. The only time you should really "roll" is across enemy ink when running away from a situation you can't deal with, or when going in for backdoor tactics. Do not toss sprinklers when advancing unless you are certain you will have time to refill/roll to a safe spot; instead opt for spreading ink everywhere.
You should seriously be scoring at least 1000 raw every time if you do it correctly, regardless of win or loss. This thing is just incredible at spreading ink...use it!
Still, if you can get to where you want to go in those 30 seconds you can really put those speed boosts in walking and swimming to good use in harassment.
I wouldn't bother. You probably won't be really walking anywhere, and there isn't a substantial amount of ink to swim across before 30 seconds have passed unless you have stayed way behind everyone, in which case they likely haven't inked the high-point areas around base and I would be concentrating on those to build special instead of catching up to mid.