That's weird, I've only ever used "subscription" as per this definition[0]:
"A subscription is an amount of money that you pay regularly in order to belong to an organization, to help a charity or campaign, or to receive copies of a magazine or newspaper."
I get what you mean and I think the other guy was indeed misleading about this, but there really are lots of contexts where subscriptions are free. In the classic postal sense newsletters are mostly free (and yes, mostly spam), when a program "subscribes" for events from another program there isn't cost involved; and most importantly youtube channel subscriptions exist.
I also had the impression he implied paying for lichess, but technically the word subscription doesn't necessarily have that meaning in our current time any more.
The most commonly used meaning of “subscription” is literally “the action of making or agreeing to make an advance payment in order to receive or participate in something.” And if the original commenter didn’t mean to be misleading and meant they had free accounts on both services, why mention having a “subscription” at all? It’s completely irrelevant.
If you subscribe to a YT channel, you would just say you subscribe to the channel or you are a subscriber. You wouldn't say you have a "subscription" with the channel. That makes no sense.
This is way beyond the original point being made, but in the YT app, the button to view channels that a user has subscribed to is indeed labelled "subscriptions".
I agree that in this context, the natural interpretation of the word is that money has been invested.
"A subscription is an amount of money that you pay regularly in order to belong to an organization, to help a charity or campaign, or to receive copies of a magazine or newspaper."
[0] https://www.collinsdictionary.com/dictionary/english/subscri...