They were much better for making a call from a public phone. They cut down on outside noise like traffic, and if the weather was bad it sheltered you from the elements while you made your call. They also provided some privacy from folks walking past. Why did they take them away?
Probably because the new versions are cheaper and (in the case of airports), you can put more of them in the same space. I’ve heard stories that AT&T also didn’t want them to be used as shelter for the homeless, but that may be an urban legend.
I think it has mainly to do with wheelchair access. You are not alone in your perception. Check this out.