They are not really, really essential. No cookie is essential. A long, long time ago I worked with a web system that kept session info in a URL parameter, and carried it over all the links. I think it was a C# website, but I'm not sure.
I love those systems. Especially when the unwary users share links, accidentally letting other users into the site as them. Or when google indexes it, and in addition to terrible security, the site uses regular GET links to perform site actions, so google deletes the user's content or buys a bunch of stuff as them while walking the links it finds as it indexes in beyond the user's initial account bearing link.
lol. no.
The problem is it’s makes urls horribly unwieldy if a user wants to bookmark or paste in links from emails etc etc, or writing JS to interact with links, not to mention the security issues of being able to accidentally share your session.
Possibly, yes, but not at all user friendly.
It also poses a security / opsec issue if anyone non-technical wants to send a link to a friend / co-worker. You may compromise yourself.
If people share their screen people would be able to hijack the session too.
You won't be able to distinguish device sessions from one another reliably neither. Think of "log out all other devices".
These are what I can think of. There's probably a handful more reasona NOT to do that.
You could, I think. Passing the session ID in the URL is the same as storing it as a cookie. You can invalidate both in the server.
Link sharing is an issue, for sure. You could tie the session id to the IP, but that doesn't work when people share their IP, which is more and more common every day. IP tied session would work better with IPv6, though.