It's totally conceivable for a new/junior employee to spend hours or days solving a problem that's already been solved in your codebase, and someone with experience could fix the issue in literally 5 minutes or less.
Yes, it's good to learn things on your own. But especially in a small environment, sometimes you gotta move faster than that.
Sometimes getting an answer 1:1 is "empty calories", and you're not learning how to solve the problem.
But that might be because the problem doesn't need to be solved, and you were wasting hours or days trying to solve it.
Which is fine for some things. But also really really bad for virtually everything else. It's exceedingly hostile, especially for places where there is no written documentation, and lots of old timers who have tribal knowledge and are "far too productive" to answer messages.
Juniors aren't born knowing any of those things.
* If you go through the process of figuring it out, you gain a durable understanding of the subject matter which you can use to solve other problems.
* If either you (after your investigation) or the subject matter expert (on request) produces documentation of the subject, other people in the future can use this artifact to unblock themselves.
* If you ask in a public Slack channel, at least those who are channel-surfing or searching during the retention period might see it and learn something.
Getting an answer 1:1 is empty calories. It gives quick satisfaction in the moment, but only leads to more and more communication down the line. Communication kills productivity.