I used Sage a couple years ago for a cryptography course. I share your opinion, many times Sage was confusing or even frustrating. But I'd still say it's a grea

I used Sage a couple years ago for a cryptography course. I share your opinion, many times Sage was confusing or even frustrating. But I'd still say it's a great project, very capable, and... Mathematica is really expensive. Sage being open source and free is a real asset. This said, I don't think you should "learn" much Sage. At least if you know Python already. Just search for what you need when you need it, write the script you want... and that's it. Unless you are using it daily, at least.