It enables generic medicine - as patented medicine needs to publicly disclose methods. It also allows the public to know what is in the patented product because it is public info.
It also makes iteration easier, as everyone can build off and on top of the patent info.
However, patent abuse is a real issue. Using patents to stifle others innovation and create monopolies. Also patents that come about from publicly funded research often give private companies exclusive rights to profit from work funded by the public.
Mickey mouse is copyright, which is a different beast. It’s also good because it protects people producing easily copied work such as writing, music and images. However, the mouse has lobbied his way into making the copyright protection excessively long. It should be much shorter, 30 years since publication would be reasonable - it would be a tremendous victory if we got it down to 50.