As a negotiating tactic, I suppose a "practice strike" could have some effectiveness -- not in terms of instilling fear in Delta management, but as a device to get the pilots' viewpoint presented before the public. I'm sure there will be numerous TV interview opportunities.
I certainly wish Delta's pilots well. I hope the airline keeps flying and the pilots maintain a living wage, with benefits.
But again (and I know I sound like a broken record here), ultimately it's going to come down to fundamentals, and the most important fundamental for airlines is whether they can offer cheap fares and still be profitable. In order to do that, cost-cutting will not come in waves or phases -- it will continue to be an omnipresent, overshadowing, relentless fact of life. This means downward pressure on pilot compensation will not cease. The looming question for pilots (in the US, anyway) is "Can I reconcile myself to a salary roughly equivalent to a big-city policeman's?" Those who can answer "yes" to that question have a good chance at enjoying their flying career. Those who can't answer "yes" should either look for a new career or resign themselves to a flying career marked by bitterness. Sad, I know, and I wish it were otherwise... but that's the new landscape for airlines.