They're worth the money for me at least since I own a $600 desktop DAC myself. My point is that in my experience, there's only a minute improvement in sound quality from tiny portable DACs / DAPs at $300 or less price point. To me it's not worth it. I don't exaggerate improvements on DAC or Amp or even cable upgrades like many audio enthusiast do (I know I'm generalizing), but realistically, an improvement from a freebie earbuds to an entry level audiophile HP is 90% better than using a good pair headphones and just upgrading the DAC. However, upgrading to $500 or higher priced DACs, I do notice an acceptable difference and I believe even the most noncritical listener will hear without even focusing on the music: the sound becomes transforms from flat to alive, more depth, soundstage, detail, timbre, etc.
TLDR: IMO, Cheap DACs are rip off (little bang for a lot of buck since they sound almost the same as a clean on-board audio that is now a feature of recent DIY computer kits) while mid tier DACs get reasonable bang for buck since I can clearly hear the improvements without feeling that I'm just being deceived by confirmation bias.