How necessary is the not keeping logs thing(unless of course they too sell the data)? Sure if someone is hunting you down and the VPN keeps logs, then they can

How necessary is the not keeping logs thing(unless of course they too sell the data)? Sure if someone is hunting you down and the VPN keeps logs, then they can easily figure it out. But if you're just trying to avoid your ISP selling your browsing data, do you need to be concerned about what the VPN provider knows? Would the ISPs go to the lengths of trying to get that info from the VPN?