Think before do. This is just an optional payment service provided by Windscribe. And honestly, for free users like me, this is not really a bad idea. I wouldn't personally use this but for some people this can work.
Nothing is done in secret. There is a choice. Unlike whole ccleaner debacle.
Uninstalling Windscribe is not an option for me. It is one of the good VPN's. When my license expires, i will use the free 50gb/month option. Windscribe alternative - ProtonVPN is an hassle for me, as to use it i have to install it's app & on top of it, it uses powershell scripts in it's installation, which i had disabled.
FYI - Kaspersky detects the secret coin-mining scripts & webpages. So nothing to worry about.