Number 2 is a great point. That's what I hate about LinkedIn and why I only use it to look/apply for jobs and occasionally scroll through if I'm super bored.
My experience in my current job are endless cold emails from salespeople who don't even understand that I have no use for their product. I work in a field where I have to research a lot of different equipment/parts for my client, but that I don't use myself. I had to request a catalog from one of these places which involved giving my work email address. Now I get endless emails about how they'll 'be in my area' (LOL no you won't because I work remotely across the country from both my company and my client) and they want to demonstrate their new product...which I don't use because I don't work in that field. Makes me laugh every time and yes it is very spammy.