But there are other considerations. The constraint solver in flexbox used to be a lot slower to render than other layout methods. And if you have experience in non-web UI frameworks, you can see that flexbox isn't that different from things you can find in Swing and Qt, so you can just wait a while and learn it in a day when you need it.
I've seen nigh unmaintainable web apps that were entirely laid out in really overwrought nested flexboxes, when using utterly basic HTML elements like <p> and <h3> and <dl> with a bit of CSS would have rendered faster, been developed faster, worked in older browsers, and worked better with accessibility tech.
So really, flexbox is just another new old thing, and what matters is the concept of constraint-based layout as one tool out of many. If it's the first new thing you encounter in your career, it's worth learning it because it's there, but remember that it's just another spoke on an ever-turning wheel.
I've seen nigh unmaintainable web apps that were entirely laid out in really overwrought nested flexboxes, when using utterly basic HTML elements like <p> and <h3> and <dl> with a bit of CSS would have rendered faster, been developed faster, worked in older browsers, and worked better with accessibility tech.
So really, flexbox is just another new old thing, and what matters is the concept of constraint-based layout as one tool out of many. If it's the first new thing you encounter in your career, it's worth learning it because it's there, but remember that it's just another spoke on an ever-turning wheel.