What is difference between us05web.zoom.us and zoom.us

what is difference between us05web.zoom.us and zoom.us?
Here it is mentioned that “Its just using a subdomain DNS server of Zooms to take load off the main domain and it happens for free version”. Is it so?

My guess is it’s faster or more efficient to direct you to a regional subdomain where your account data is located (rather than having to figure it out on each request). It may also be easier to comply with local laws if you can ensure that customer traffic remains in the same region.