Yes, really big. And that was many years ago when I had a pair of €25 HD220, with better headphones it's probably more noticeable but I can't confirm that. I'd recommend you to get the one I have so you're set for good instead of getting a cheap one, discovering what a difference it makes and then getting a better one leaving the first one obsolete.

And another benefit of having a dac is getting a constant sound quality regardless of what device you use as a source. Maybe your PC produces a decent sound but your phone doesn't so you'll be stuck with the device that sounds good. Which btw is a good reason for not going with one that takes power from the USB like my previous e10k.