AutoRenewals

Recently, I got an offer for 'try linkedin premium for free'.  I noticed in the fine print that it appears that this is one of those 'you will be autorenewed and your credit card will be automatically charged unless you go out of your way to opt out in advance' deals.  I know, ahem, some online dating sites I use are like that.  I also remember I had a free trial of amazon prime that did something of that nature - I wrote an email voicing my discontent & received a refund.  Also, recently, a friend of mine got a free trial of some vitamins that operates the same way.  

My question - why do companies do this?  I mean, I do get it.  They then get to charge for an extra month of whatever.  They decided the customer relationship continues - it might be an easier way to rope in customers that wouldn't go out of their way to 'opt in', but will let it continue out of laziness/indifference.  However, does anyone LIKE this business practice?  I find it annoying.  I'm guessing most people do.  I know, like I mentioned with amazon, in most instances, annoyed customers can get a refund when they did not want to be renewed and are shocked to discover a random charge on their credit card bill.  And if they cannot, usually the business can get an extra month or so of payment out of said individual, but then they lose the person as a customer for the long-term.  And, generally, I feel most people are annoyed by this practice, so it negatively impacts a customer's view point of the business, even if their pocketbook is not victimized in the end.  

What are your thoughts?  What are the benefits of the 'autorenew and automatically charge after a free trial' (or ending paid subscription)?  Are their any benefits for the customer?  Are there any customers out there that like this business practice?