The major benefit of a "formal" education (or in learning from someone with lots of experience) is that they have a better feel for the overall territory than a novice. They can help guide you towards the direction you need to go.
Learning by yourself should obviously be encouraged, but it's often difficult to know what thing to learn about next in order to ensure that the new knowledge integrates well with what you already know and (pragmatically) helps you solve the problem at hand.
To give a specific example, I'm lucky enough to sit next to our chief infrastructure engineer at work and he has helped me learn a huge amount about Linux over the past three years. He hasn't done this by giving me "formal" instruction, but instead he's pointed me in the right direction when I get stuck with something.
Learning by yourself should obviously be encouraged, but it's often difficult to know what thing to learn about next in order to ensure that the new knowledge integrates well with what you already know and (pragmatically) helps you solve the problem at hand.
To give a specific example, I'm lucky enough to sit next to our chief infrastructure engineer at work and he has helped me learn a huge amount about Linux over the past three years. He hasn't done this by giving me "formal" instruction, but instead he's pointed me in the right direction when I get stuck with something.