No disrespect, but that (amateurish) attitude is precisely one of the things which has held back Coaching on these islands, and explains why so few British/Irish people coach abroad these days.
The best way to think of it is to replace "Coaching" with "Teaching" - you never send a teacher into the classroom unless he/she had a degree and a relevant qualification, even though some without them could do the job well and those with them cannot.
These days, as well as players, Portugal produces top Coaches/Managers out of all proportion to its size. And the main reason is because they treat it very seriously as a Profession, with internationally-recognised University degrees and the like, eg:
https://football.fmh.ulisboa.pt/