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A good utility is custom-made for a job. There are many link checkers out there, but none of them seems to be striving for the following set of goals.
You want to run the link-checker at least before every deploy (on CI or manually). When it takes ages, you're less likely to do so.
linkcheck is currently several times faster than blc and all other link checkers that go to at least comparable depth. It is 40 times faster than the only tool that goes to the same depth (linkchecker).
No link-checker can guarantee correct results: the web is too flaky for that. But at least the tool should correctly parse the HTML (not just try to guess what's a URL and what isn't) and the CSS (for url(...) links).
linkcheck doesn't attempt to render JavaScript. It would make it at least an order of magnitude slower and way more complex. (For example, what links and buttons should the tool attempt to click, and how many times? Should we only click visible links? How exactly do we detect broken links?) Validating SPAs is a very different problem than checking static links, and should be approached by dedicated tools.
linkcheck doesn't validate file system directories. Servers often behave very differently than file systems, so validating links on the file system often leads to both false positives and false negatives. Links should be checked in their natural habitat, and as close to the production environment as possible. You can (and should) run linkcheck on your localhost server, of course.
