The advantage of a web app is that it can be distributed in any number of ways though. It's trivial to take it and re-host it on different servers, as an onion service, or go the full decentralized route with IPFS or similar.
99% of the people are on the big email providers.
Also, you will quickly find out that sending many emails from random addresses (ie: spamming) doesn't work these days, they will be blocked by existing anti-spamming techniques, as evidenced by multiple posts on HN of people trying to do that from their own mail server.
You need to go through a whitelisted mail service (MailChimp, ...) which is another block point.
You don't need to mail links, you just need to mail required information. Asking Google to filter out some specific e-mail (which could be somewhat randomized for every recipient) probably will not work.
> You need to go through a whitelisted mail service (MailChimp, ...) which is another block point.
Russia can't ask US service to deny making business with US citizen (for example). It's completely outside of their territory.
Not sure what US citizens have got to do with this. Russia obviously was able to order Google to block relevant apps and documents for Russian people. Why would they care that US citizens can still access them?
Already if you go in a country with restrictive internet, you'll find the average working-age person knows how to use a VPN. Regular drug users in western countries know how to use Tor. Hong-Kong protestors were using a bluetooth mesh network app.