How do you view o3? I personally find it superior to google search almost always. Do you find that it often misses key references? (also mathematician)
Google is completely inadequate at mathematical search. But here is a concrete problem that no search seems to handle: given some complicated integral (say, some contour integral involving a K-Bessel function), find where it appears in the literature.
Most search will totally fail, because this is made of math symbols. Embedding-based search will give various related things involving, say, integrals and Bessel functions. But then I end up opening Gradshteyn and Ryzhik and trying to find where in this book the relevant terrible integrals appear.
This is a common experience for analytic number theorists. And it's a lousy experience.
Interestingly, one of my biggest problems with Gmail is that they don't allow actual plaintext. I used to routinely collaborate with developers who were vision-impaired, and the official Gmail phone app wouldn't let me send them plaintext email. Instead, it was some sort of HTML thing. Unfortunately, we sometimes sent code snippets to each other over email, and though admittedly it looked more or less fine, Gmail changed the underlying representation enough that my collaborators' screen readers would mess up on the parsing.
This led to me leaving Gmail on my phone, which led ultimately to me leaving Gmail entirely.