“… but it make no sense to opt out of the subscription at the time of subscribing.”
This is used often in “free trial” offers. For example, I got 3 free months of Apple TV because I got the battery replaced in my IPad, (They actually just gave me a refurbished IPad.) Apple signed me up for automatic payments after the three months expired, but didn’t really point that out. If I had known, I would have cancelled when I got signed up. As it was, I didn’t find out until I got billed for the fourth month.