Is it still worth it to protect our software against piracy? Are there reasonably effective ways to prevent or at least make piracy difficult?
Not really.  Any copy protection has to be 100% perfect, (which we all know is impossible,) or else all it will take is for one person anywhere in the world to come up with a working crack and post it on the Web.

If you want people to pay money for your product, copy protection is not the answer.  It never has worked and never will.  The answer lies in Economics 101: people will pay money for your product if they perceive its value to them as being greater than the price you are asking for it.  Otherwise, they won't.  Period.
