Domain _experience_ is what hiring managers look for. If there’s a high-paying job in some rarified field (say analytics, algo trading, low-latency..) then domain experience on the resume is the crucial factor. Many candidates can have strong tech background, and strong domain knowledge, but only those with “relevant experience” will get short-listed, or those with good recruiter connections.
The domain experience shows in terms of 1) jargon 2) architecture, but actually is very local and not portable at all.
Generic domain knowledge is very “thin”. You can pick it up by reading or over a few months on the job. Mostly jargon terms, and very little math. Hiring managers ask questions to verify such knowledge but it’s not hard to pass.