Here's my opinion based on my experience, FWIW.
I've been playing guitar, self-taught for 40 years, but only seriously for the last 6 months. I can play in public (where I can work around mistakes), and can record after an excruciating number of takes.
I think a teacher can add value to your playing prowess and progress. The trade-off is what the cost is worth in relation to your goals.
If you want to be the next Carlos Santana, then a teacher is probably the only way you are going to be able to get there eventually, faster than you could learn with a day job and only spare time to practice.
If that's not your goal, but you want to play some songs for your friends, I think you can learn by yourself with the internet.
There are lots of lessons here and many posts pointing to other site's lessons.
For that goal, you need to learn strumming and chords and changing chords. You can learn strumming from many of the lessons here. You can learn chords from Kirk's book or from other sources. You can learn chord changing from just doing it a zillion times.
Although a teacher might speed up the process and point out wrong things, the price might not justify such attention when viewed in the context of your goal.
Playing lead is a whole different matter - there are techniques that a teacher would know but you would have a hard time discovering by yourself. Simile all the effects like wah-wah, etc.
Playing finger-style can be learned from Kirk's lessons, but even in my case, it's a bit too advanced yet. However, I think it can be learned sufficiently from Kirk without the expense of a teacher.
One related concept is to have multiple practice aspects available, so you can vary the experience and not get into a rut. For example, you might practice scales one time (or part of a practice), practice chord changing another, practice bar chords another, play along with the
radio another, play old songs just for fun, etc.
If you just play Mel Bay every day it's easy to see how that would get to be a grind.
I think there have been many threads on what to practice and people hitting a wall, so there's surely better advice in the responses to those than I can give.