There were other, substantially larger bonuses for innovations made by staff, when these innovations had larger economical impact (for instance, optimizing the production line).
I guess that that is the point. I worked for a similar company. They were not interested in groundbreaking one-of-a-kind patent. They were looking for something to use as a countermeasure if another company in the same sector sues them.
A new chemical process, a new antibiotic, or something of that scale can be used to create a new successful product, save lives, etc. Patents were designed to make sure that companies could profit from them, but that the knowledge was not lost just because they keep it secret.
In software development, I have seen a lot of "method to send content to a remote storage using gesture-based commands" (this one is made up). When they just mean that a developer implemented a drag & drop touch functionality for the phone that sends a file to a server. A necessary implementation, but hardly an invention as any developer will come with a similar solution in minutes if presented with the problem.
The one patent per Scrum sprint program, bred a whole encyclopedia of "apparatus or algorithm for searching, publishing, or displaying a thing within another thing" patents.
I had a friend whose father was getting royalties for some chemical manufacturing process that he came up with. I recall that royalties were planned to be a major component of his retirement.
It's interesting that for execs big bonuses for good work are considered motivational and necessary whereas for the little guy good work doesn't need to be rewarded because it would add cost.
In my current role we have a similar program, beyond the relatively small bonus I think the only benefit is bragging rights. Patenting or inventing something means little to superiors. Large companies focus on the short term stategic initiatives, often being unable to capitalize on long term or even short term opportunities. That's why more nimble startups are more effective.