Since it is similar in description to alien abductions, it's no wonder skeptics like to cling to this as a reason why abduction is not real. What if they were right, at least in the sense that the abduction phenomenon is connected to sleep paralysis, but in a totally different way then the skeptics believe.
It has been thought that while you dream you sometimes can have things happen to you physically. For instance, I've had dreams where I'm falling then suddenly find myself awake with and my leg jumps as if I've landed on it. A little bit more extreme is the idea that dreams can take you to other real worlds/dimensions. Perhaps the aliens committing the abductions only physically abduct people a few times and the rest of the time use dreams and/or sleep paralysis to their advantage, using the so called "implants" found in some abductees to initialize the abduction experiences and doing what they do in a dream world.
Throwing out the more far fetched ideas of that theory however, aliens could perhaps be aware of the sleep paralysis phenomenon and simply use it as a cover for abductions. Triggering it to make abductees believe they are simply experiencing this ordinary phenomenon when in fact they are unaware they are being taken by alien beings. Just another arsenal to hide their actions just like screen memories.