I report each one. And after 6 months maybe 10% are addressed. There are many basic corrections that have been reported multiple times that are not corrected after 6-8 months. They clearly do not have the staffing to respond to the quantity fo reports.
I always do both. Given months and even over a year go by without corrections it is important for others to see the issues in the comment section also. If corrections were being made within a couple of weeks that would not be important.
I agree with ChstlesE780046, I do get intermittent emails saying my reported translations are now accepted, usually long after I have forgotten all about it, so this is the best way of improving the course and helping other learners.