I full well understand why llEmail - which can be used to send emails to inside AND outside of SL - has a 20 seconds forced delay.
However, when used only inside of SL, using the lsl.secondlife.com namespace for object-to-object communication, the delay seems excessive to me.
llEmail is basically the only(!) way for object-to-object communication that is reliable over long periods of time without the need to cache ephemeral URI's like we need with llHTTPRequest, where the URI changes with each restart. llEmail used in conjunction with an object UUID will run come hell or high water.
Making llEmail in the lsl.secondlife.com namespace run with the typical 2 second delay (or less even), would allow scripters to keep more communication inworld and rely less on external servers.
/me waits for the bot to turn it to "tracked"