I went from an Amazon Fire Tablet to an iFi Zen Stream, and the improvement in sound was very noticeable. A neighbor went from an Apple laptop to a Node and said he experienced a big improvement in sound as well.
From what I’ve read, you’re decreasing the amount of noise that’s getting through; noise you don’t realize you’re hearing until it’s no longer there. I can’t give you the technical reasons why, only that the sound jacks in laptops and tablets aren’t made for hifi purposes, and sound like it.
Also, as someone else mentioned, it’s wonderful to no longer have a wired remote (like some early ‘80s VCR).
It’s win-win, and you will only curse yourself for not having done it earlier