There's also the reality that using your ISP's DNS almost entirely moots any VPN you use. The main reason to use a VPN is to hide your browsing from your ISP and anyone your ISP might be reporting to (in the US for example we've seen several programs where the government intercepts ISP data at special places in interconnects, so even if your ISP publicly says your DNS is safe, it could actually be logged to a spy database associated to you)

When you use a VPN and then immediately send all your DNS lookups right back to your ISP... Hey I wonder where this person is actually from! Maybe the geographical area of the regional ISP that all their DNS lookups are coming from...