Realistically, the reason people do most of the things they do, is tradition / habit. Such-and-such is what I learned in graduate school, it's what I've always done, it's what everyone else in my field does, it's what reviewers / editors / readers will expect and understand readily.

Having said that, we can ask if there is any better justification for bar charts with error bars over boxplots. I agree that boxplots do show more information on the whole, but something can be said for bar charts:

1. People are typically interested in group means. Bar charts display means directly. Boxplots, by default, do not display means, although they can be augmented to do so.
2. People are typically interested in inferences about means. The error bars on bar charts, while they can be tricky in some cases, do display information that is relevant to the inference about the means. Boxplots, by default, do not, although they can be augmented to do so.
3. People are not typically primarily interested in various quantiles. Boxplots make it easy to see the median and quartiles, and the minimum and maximum values. I think these are interesting, but they are typically not what researchers are theorizing about. Bar charts do not display this information, which people might consider extraneous and adding 'clutter' to the display. (I don't really agree with that take, but I'm well aware that many people hold it.)

In short, bar charts display what most end users want to see, and not what they don't. It's the opposite for boxplots, although I do wish these attitudes were less prevalent.

Realistically, the reason people do most of the things they do, is tradition / habit. 'Such-and-such is what I learned in graduate school, it's what I've always done, it's what everyone else in my field does, it's what reviewers / editors / readers will expect and understand readily.'

Having said that, we can ask if there is any better justification for bar charts with error bars over boxplots. I agree that boxplots do show more information on the whole, but something can be said for bar charts:

1. People are typically interested in group means. Bar charts display means directly. Boxplots, by default, do not display means, although they can be augmented to do so.
2. People are typically interested in inferences about means. The error bars on bar charts, while they can be tricky in some cases, do display information that is relevant to the inference about the means. Boxplots, by default, do not, although they can be augmented to do so.
3. People are not typically primarily interested in various quantiles. Boxplots make it easy to see the median and quartiles, and the minimum and maximum values. I think these are interesting, but they are typically not what researchers are theorizing about. Bar charts do not display this information, which people might consider extraneous and adding 'clutter' to the display. (I don't really agree with that take, but I'm well aware that many people hold it.)

In short, bar charts display what most end users want to see, and not what they don't. It's the opposite for boxplots, although I do wish these attitudes were less prevalent.