Hey - you're looking for a job? Come work here PLEASE!! As a company you can get folks who'd otherwise go elsewhere as well this way because process can be shorter - you've already worked with them maybe in other contexts etc.
One issue now with hiring is just the crap you have to wade through. When hiring was local and/or in office interviews it was one thing - but now it's honestly wild. The number of responses is INSANE. I used to make a point to read every resume (just a glance at least) - that's impossible now (it's slow anyways on a lot of sites to flip through resumes).
Outsourcing is definitely up as well since overall remote is up and has made that easier.
Then you've got scammers - we've definitely contracted with one person, and when talking with them later its a different person entirely. Ie, email grammar falls into trash.
In my experience, in bigger companies hiring managers seem to dislike this kind of "nepotism". The best they do normally these days is to give you the hr/recruitment email to send your application to. This is just some real-life experience based on recent job hunting.
Employee: “Hello, hiring manager. I know an incredible candidate for that job we posted last week.”
Hiring manager: “Thanks, employee, but we have hundreds of resumes from strangers, so we don’t need to talk to your contact.”
I’m not saying that never happens? But I am saying that it happens rarely enough that you shouldn’t use it to guide your networking strategy.