If you buy it for nothing else, buy it for priming your models.
Despite a lot of coloured sprays available, nothing will ever give you the range of colours (all of them) that an airbrush will for priming/basecoating figs.
And while it may take a little more set up and take down, consider that priming a model black with a can, and then spraying him with the specific can of whatever colour you want will be 30x more thick than what you'd do with the airbrush.
Seeing your models primed by an airbrush will sell you on it. You never realize how much detail you lose with canned spray (and I have done thousands of models with canned spray paint)
All that said, still a lot that needs to be done by brush after he airbrushing is done