Using a desktop email client is my preferred way to use email. I can read them even offline.
I'm hard pressed to think of a situation where a desktop app isn't superior to a website. Web apps are a port in a storm; if I can use a desktop app, I always prefer to.
Gmail has no desktop app, though it has mobile apps.
The web or PWA Gmail has more features and settings than any third-party desktop app would offer when using IMAP or POP. Gmail is a custom-designed first-party app. If you read mail from Google through Outlook or Thunderbird, it will have lowest-common-denominator features through the lens of a different vendor's structure.
Now you may consider it a superior advantage if the Gemini AI isn't available, but probably won't be able to create custom filters without the PWA.