It’s only a limitation for people who doesn’t wish to participate in the network. And that’s fine. They can still download public content for free.
@bolet75 coined the term “collaborative cloud” and this is the concept we need to drive home. This needs to be written all over the place. When it’s understood, people will naturally understand that in order to use, they need to share. It might slow adoption at the beginning but it will also make sure that the community is build of people working together.
I’m no expert but to me it’s like saying the gold you farm in World Of Warcraft should be taxable, the cards you acquire playing Magic should be taxable, collectable hockey cards should be taxable, marbles should be taxable, pokemon cards should be taxable, lol even street creds could be taxable. It might sounds like a silly comparison but when you think about it it’s pretty much the same thing: a token you get by interacting with a close system that allow you to interact back with it.
If you sell your Safecoins for fiat then it’s another story. Anyway that’s how I see it. Until proven wrong, I’ll farm to my heart content 
EDIT: Thinking more about it, the line is probably when you decide to use your Safecoins to buy something outside of the network: a pair of boots, a song, a movie, etc. Then it’s probably less of a gray area. But if all you do is spend it to put your data on the network, I wouldn’t worry about it.