Someone actually still uses the built-in podcasts app?
Not sure what you have against it. Works great for me. No subscription required. And if I do want to pay for ad free shows and support creators it's easy to do so.
Use whatever you like but I don't think Podcast app users are rare by any stretch of the imagination.
It's absolutely fine, from what I can tell
AFAIK the native Podcast app for iPhone is the only way to make PC-phone podcast file syncing work. This stops you downloading the same podcast file twice, once on your PC and once on your phone.
It probably has more active users than all third party podcast apps on all mobile platforms combined. The power of defaults.
It's generally a good app. People in the tech community like Overcast, but I've always found its UI completely illogical. Apple Podcasts is organized like I'd expect a podcast app to be.