Nowadays, I don't know what to think about built-in dev tools. On the one hand, they promise lowering the entry barrier for fellow ongoing devs. On the other hand, they apparently aren't, because many folks don't care about learning all the basics of HTML, JS, CSS, etc. any more but instead prefer to enter the development world on a framework level. Developer extensions like "Vue tools" make stuff only more complicated, not less, thought.
IE developer toolbar was actually better for quite a while too.
Then Chrome came out and most people switched to that, partially as the Dev tools were great, although, again, initially lacked some features so I tended to use a mix of both for about a year. But Google iterated fast and firebug got clunky.
Those tools blow even today's Chrome and Firefox dev tools out of the water in terms of accessibility, both in terms of keyboard/mouse and discoverability of interface.
Sadly, few people had access, because you had to either pay or pirate.