I have one for my tablet and one for my iPhone (one USB-C and one Lightning adapter).
Both are flimsy even though they’re branded. My earbuds have a pretty strong twisted modular cable, the adapters make folding and unfolding my cables annoying.
The adapters also tend to get caught on things in my backpack and detach themselves from my earbuds.
I also use my earbuds on devices that do have a jack, so I have to constantly remove and re-attach the adapter (or go looking for them).
They’re visually annoying as well. Both are white, my earbud’s cable is copper. If you have headphones or earbuds with an angled jack. The adapter makes the angle comically and annoyingly large.
The adapter basically suffers death by a thousand papercuts for me. They’re annoying, obstructive, makes it harder to get listening to your music and they’re ugly.