Of course. That's what I'm running (configured to use the ISPs DNS if it doesn't have valid data in its cache). But the first request of the OS within the TTL

Of course. That's what I'm running (configured to use the ISPs DNS if it doesn't have valid data in its cache). But the first request of the OS within the TTL of the record in question is likely still much faster served by a DNS server used by more people than just me because the server might already have answered a query before me.