It's only a waste of time if you make it a waste. Just agree to hit with whoever asks, and then use it as an opportunity to practice either being as aggressive as possible or as consistent as possible. If you ever reach a level where the "hackers" can't win a single point against you and are flat out humiliated, they'll probably stop asking to hit. Until then, you can still improve by playing with them.
Agree with this. My wife started playing about 18 months ago. We like to got out and hit against each other. While it's not competitive I force myself to play out of position. Maybe go to the net more than I normally would in singles. I use it as a chance to work on my technique and placing the ball in certain spots.