Namecheap blocks you from logging in if you are connected to some VPNs. Attempting to log in returns an error saying that the username/password is incorrect, and you won't be able to interact with Namecheap until you turn off the VPN. If you are using one of these VPNs, Namecheap is simply not a feasible option.
There are less expensive options than both GoDaddy and Namecheap that do not have any of these issues. The renewal rate for a .com domain is $17.99/year at GoDaddy, $8.88/year at Namecheap, $8.56/year at Porkbun, and $8.03/year at Cloudflare.
A bit understandable from an anti-fraud point of view.
Seems a bit strange that someone would be willing to hand over their Name, Address and payment for a domain, but not willing to show up not behind a VPN.
I am not aware of any other domain registrar that blocks VPNs, so the fact that Namecheap does is a drawback that is particular to Namecheap.
It's inconvenient to turn off a VPN just to use Namecheap. Although Namecheap already has my information, if I have more than one browser tab open and need to do something on another site while interacting with Namecheap, I would be exposed to an unprotected connection with not only Namecheap but also the other site. This is unacceptable considering that other registrars don't have anti-VPN restrictions.
There are less expensive options than both GoDaddy and Namecheap that do not have any of these issues. The renewal rate for a .com domain is $17.99/year at GoDaddy, $8.88/year at Namecheap, $8.56/year at Porkbun, and $8.03/year at Cloudflare.
https://www.cloudflare.com/products/registrar/
https://porkbun.com/products/domains