I recently tried to switch from vim to Emacs with spacemacs. I enjoyed it until I discovered Emacs has no support for tabs (ui tabs, not the character ;). I went back to vim mainly due to that, but still miss magit....
Emacs is kind of like an editor construction kit with a basic sample, and making your own Emacs variant is part of the experience IMHO. It's not to everyone taste of course (and that's ok). If not, there are Emacs distributions like spacemacs but their choices can't fit each person perfectly.
It may not be built-in, but saying Emacs "has no support" for tabs when there are at least three (if not more) plugins which provide them is a stretch. Personally, I use elscreen, but forked and changed so that tabs are displayed in a reserved window instead of on the header line.
There are some lacking features in terms of GUI display, especially compared to newer editors, but other than that Emacs supports the widest array of features and sometimes even a couple competing implementations for them.
C-x C-b
shows you the list of tabs ("buffers") and lets you select from them easily. As a bonus, the title portion isn't compressed to incomprehensibility when they get numerous.
Say I code in Python, with docs and shell windows on the right. Then I want to quickly take a look at git history. But, if I start magit, it will hijack the window configuration and my carefully placed/resized windows will get messy. So, I open a new tab and start magit there. Now, I can switch between the two tabs - ie. window/buffer layouts - with a single key.
The fact that I mention saving the layout of windows should hint that I know you can do this in vanilla Emacs by saving and restoring window configurations, but it's much less hassle with tabs. Also, you can hide tab bar (as well as menu bar and button bar) when you don't need it, and it's actually quite handy when you do need it.
To each their own of course, just saying there are good uses for tabs in Emacs, unless you want to delegate this to your WM and launch one frame per window config.
You mention window configurations, and you say " it's much less hassle with tabs." You can assign a single key to switch between window configurations too and then it's practically the same, isn't it?