" The one thing that 20 years in the audio enthusiast community (not a fan of the audiophile moniker) has taught me is that everyone's ears are different. What is "worth it" to one person may not be to the next "
God. Finally someone posting something that actually is solid advice, without linking gear that all costs 1k+
Another good point that you brought up is sheer quality. I've often found that most budget audio equipment, be it a DAC, headphones, mics, turntables, speakers, etc, (and really, any budget item) may work and function fine, even great in some cases, but often aren't built to last. I'm talking the super cheap items like the DAC the OP posted.
Investing in a solid piece of equipment is never a bad idea if you know it is something that you'll be using a lot. This often just means doing a little bit of research on your own to see what a good budget option is without busting the bank.
For audio, I think it is important to start with something on the lower end of the spectrum and work your way up, that way you can tell if something is really worth the price for you or not. I will say the first big upgrade (decent headphones + DAC + amp) instead of just listening to $10 earbuds and and iPhone will be the biggest upgrade you will ever have. Getting modular equipment, and not "all-in-one" stuff is also key, this way you can continue to upgrade your system without having to replace it all at once.