I learned on crap gear, and while yes, it can be helpful, it can also cause just as much harm as it does good. The pro's of learning on a poor acoustic guitar that is hard to fret, and has high action, are... finger strength, and stronger, and possibly faster, finger independance. However, it can also cause you to form bad habits. You'll tend to want to fret the strings much harder than needed, which can cause you to make the fretted notes sound out of tune. It's also hell trying to go from a crap acoustic to an electric guitar. It's almost like having to learn how to play all over again. There are many other possible bad habits to be formed as well, but it really just depends on the person.

I say, learn to play on what you plan on playing for a good while. Learning on crap gear can be frustrating, which can prolong progress. A similar situational example.... If you're learning how to play the electric guitar, and wanting to eventually be in a band, would it be better to learn and practice while sitting down, or standing up? Of course, it would be much better to learn and practice while standing up, because that's how you'll most likely be playing while in a band. Also, learning on the gear you plan on using for a long time is the best way to get completely familiar with your gear.

It's all personal preference, but, speaking from experience, I dont' suggest learning to play the guitar on a crap/hard to play guitar. YMMV