Why do people build Akali Tank?

Just a disclaimer: I'm not mad that people do, I'm just wondering why someone would opt for no CC and a tank build when there are plenty of tanks as mobile as Akali that could actually do something post-lanephase.

I'm just really wondering this. I can understand a beefy damage build, but I'm seeing some people build full tank, even on teams that need an assassin or a real tank.

I've gotten the argument that she can "zone" enemies with her pressure, but she has very little pressure and nothing to ensure that ranged champs won't just target someone else and survive her lack of damage with their own lifesteal.

That just makes her a tank who can easily make the excuse "most damage, so it wasn't my fault" due to Akali's ability to spam high-base damage moves, but with absolutely no way whatsoever to engage and no CC.

I get that she's not a good assassin right now, but that's not going to make her better at anything else. They even took AWAY the defenses she gets from the cloud, so it's less viable than it might have been before now.