Yeah that’s definitely one way of looking at it.
If you don’t pay for WARP then you do only get the minimum usage of their network and the costs on their infrastructure is really minimal. They benefit much more if you use the app however and not a standard wireguard client - the app is basically a network testing node that provides networking analytics to cloudflare.
They say they keep logs for 2 days and ‘anonymised’.
I think that their core business does have a coincidental benefit that allows them to offer something for ‘free’ without monetising it directly and selling information on the sly. I think the more concerning part is that it is a US company subject to NSLs.
If you are in the US then WARP is clearly an improvement on ISP ToS which can include injecting adverts and flat out selling your data.
For others in the world it is a little more nuanced. Still a useful networking tool though - and running it on a wireguard client is obviously much better from a privacy perspective than using their app which is constantly reporting metrics.