Glad you like it! Funny thing, "I didn't know i needed this" is the most common feedback we get. :)

Resizing is on the list, although it will impact the image quality if you resize up. On the same list I have making the window transparent so you can see content below it.

Not sure if I understand the second one. Do you mean quit Snappy after closing all snaps? (it's quietly sitting in the top bar)