Okay I have to say this and it needs to be said right now:

Their website design has been and remains just as awful as their mobile experience. What matters most, if not the only thing of value at Yelp, is their data and nothing else.

In my not so humble opinion they have never, ever had an enticing UX or product beyond basic reviews. Ever.

I really don't understand why - for years you couldn't even enter a review via their app (and later you had to login to the website to complete it).

To this day, you can't so much as search the text of reviews in their app and be directed to the review containing the string you searched for. You just get results for establishments that apparently contain your search string somewhere in the reviews, and have to ross your fingers hoping that text was "the tonkatsu is great!" and not "too bad they don't have tonkatsu!"

You can! It’s just incredibly hidden. This is on iOS:

Business Entry > Click the XXX more reviews button (beneath tons of content) > scroll up and then search within reviews

Seems it even highlights the word just like on the website.

I remember I once found this and thought “Wow, their UX people don’t care”.