Language barrier.

My English is not bad at all, but to the Terms of Service, I had no desire me even begin to continue to deal with the calculator.
Sure, English is a world language, and is the program today for free but this program is starting tomorrow with costs because you should already spend the couple of toads and make one additional gearing up.
Conclusion: anyone who feels to click through a complex computer and not in one's native language can access safely, everyone else should make a big circle around the part.