Free VPNs may look great, but there are always trade-offs. And we’re talking about things outside of the scope of features offered. There’s always the chance that the free VPN is financing itself by collecting your data and selling it to third parties that can exploit it.
Surfshark, a paid app, has no incentive to do that. The company doesn’t know anything about what you do with the VPN. The app was also audited by the independent web security testers Cure53.