Without LinkedIn account I won't get a job in US?

I always look someone up by LinkedIn before meeting them. Usually people do the same for me. It's a good way to see who you know in common (better than Facebook on a business level) and in general saves a lot of time. Almost everyone I meet for work has a linkedin profile -- though literally just yesterday I (independently) met two people without a linkedin profile: one a quasi-celeb and the other someone simply so specialized in skill and so appropriately connected that it just didn't add value for him.

Now there are drawbacks to linkedin. For example some people will link to just anyone. I only link to people whom I actually know well enough personally to have a good opinion about them.

The linked in interface is terrible. It generates too many messages and basically just sucks. They know, and it sometimes improves, but there you are.

You will get recruiter and other spam. But then again the whole point of it is to connect people professionally, so...

This is not true.

I've been part of the hiring process repeatedly throughout my career, and while it's nice to find a candidate's LinkedIn profile, it's far from necessary.

In terms of hiring front end engineers, I want to see a portfolio. For back end engineers, I want to see source code - preferably on Github. But LinkedIn? That's a nice-to-have, nothing more.

In Canada, I used to get a lot of recruiters contact me from Monster and Workopolis, but now I get a lot from LinkedIn. Just a few days ago a manager at Amazon reached out to me on LinkedIn. So it's definitely helpful, I wouldn't discount it.

This is 100% false. LinkedIn will do nothing for you but make you a target for recruiters who are full of shit.

Why do you keep it then?