Disposable emails are great for privacy, but they are also a handy tool for spambots, vandals, trolls, and other troublemakers.
Also, constant email bounces/rejections are not great for our email sender's health, so knocking out a common cause is worth considering.
Skizzerz has a nice little extension that uses debounce.io - a premium service with a minimal free tier that does disposable checks but also screens non-disposable domains to determine if bounces are likely.
An alternative would be to write a wrapper around the disposable-email-detector.com API, which would do the disposable detection. This uses an open-source, collaborative list, and the API is available as an open-source C# docker container which we could self-host for better availability and privacy.