Email deliverability is the reason I gave up on email entirely for my side project and built on Telegram instead. Setting up SPF, DKIM, DMARC, warming up a domain, monitoring reputation, dealing with bounces and complaints... all of that just to maybe land in someone's inbox.
With Telegram you send a message via the Bot API and it arrives. 100% deliverability. No spam filters. No authentication chain. The message just shows up with a notification on their phone.
Obviously Telegram has its own limitations (smaller user base in the US, less formal). But for anything where you need reliable message delivery to people who opted in, messaging platforms have a massive advantage over email in 2026.