[inigyou]

P2P protocols don't have much problem opening up a stateful firewall connection as you just have to send one packet out to open a known address and port.

I prefer to run scrapers behind CGNAT because websites can't ban it without causing collateral damage, which matters more to some than to others. The website probably has to put up a captcha. Which hurts its human traffic. Think about how much more traffic you could have if you didn't show everyone a captcha, and you might see that you should also be in favour of IPv6.