Can a gradient be converted to a transparency mask?

Question

Adobe Illustrator

Answer 1

Of course you can, that's how it's supposed to be.
You take object A, overlay object B (which will be the mask). You set the desired gradient (black and white) to object B, according to which transparency will be made. White - opaque, black - transparent, gray - translucent. Select them both and go to the trasparency panel, press make mask and voila! We have an object with gradient mask transparency.
In the screenshot above, on the left is the object, and on the right is the mask.