One of the best pieces of feedback I got at Heroku was don't stress too much on it being perfect. In fact you can make it rough as if drawn on a napkin so it intentionally isn't visually polished and it accomplishes its goal. I in fact started doing some of this way back at Heroku 9 years ago and the approach worked well. Now I've leveled that up with an iPad and paper.
Yes, there are places that have designers and they're a great resource, but don't let that be a blocker. If a company has a designer that can be dedicated and support such awesome. If not just try something and see what works, then keep using it.
Now that you mention it, Ben Thompson uses this hand drawn art style at Stratechery[1] - it seems like something that is easy and fast enough to do with one of the countless iPad drawing apps and an Apple Pencil.
Yes, there are places that have designers and they're a great resource, but don't let that be a blocker. If a company has a designer that can be dedicated and support such awesome. If not just try something and see what works, then keep using it.
Edit: An example of very crude/napkin style drawing - http://www.craigkerstiens.com/2011/11/07/how-heroku-works-ma...