On Wed, 2021-01-20 at 11:35 +1030, Tim via users wrote:
Also, when using an outside DNS server, it can be a problem if you want to resolve domain names within your LAN (if you have a network of computers and other network devices). You have to do that another way.
Supplemental: It can also be a problem, with some ISPs, for accessing their services. They may give customers on their own network different IPs to connect to for their own services (mail, etc).
Though I expect that kind of thing is not as prevalent as it used to be. A lot of people don't use their ISP's mail service anymore, they use something like gmail, or their phone. So they've got to be able to carry on using services when not directly using their ISP.