Solving a well-known open problem like N-S "millennium" problem has some marketing value, as this can be referenced in a press release, etc.

OTOH a marginal value of a single paper in a paper dump is basically zero. Nobody gives a flying fuck if they made 100 or 200 papers. It won't give them even a single customer. If they released, say, 5 paper per month it would generate a buzz but not as much backlash from mathematicians.