I know this might sound naive, but if you know what the service provides (which you do) and you know how much it costs (which you do) and you know that you cancel it without a problem (which you do) - what is there to be skeptical about? They aren't going to firebomb your house while you sleep.
I signed up for BF4 and PvZ Garden Warfare. They were £25 each in stores. Paid £20 for a year's access to them instead. I'll have had my fill of them by the time the year is up. If I bought them and traded them in a year later, I'd probably get £10 for the pair, so the same playing time would cost me £40 at retail. Plus there's likely other titles coming up of course. And NFS Rivals, which is fun for an hour at a time.