they are good but need maintainence, if you cross rivers/ puddles, they need to be checked because they will actually hold silt where without them it would just wash away.

In mud (like your photo) that sticks they for sure add protection, but you could also use mud scraper dust covers too, SKF makes them

For more road biased riding they work, I have had some on my Super Tenere for 81,000 miles and no issues...but did they ever stop a potential failure? Conjecture!