I’ll take “Why developers drink for $1000, Alex”
Maybe, maybe if CCP exposed their in game mail API using the industry mail standards then maybe somebody could figure out how to configure some off the shelf webmail package to work with it. But they did not. As an added extra bonus CCP uses its own proprietary markup so good luck rendering that without heroic measures.
And yet there are still calls in the latest API (ESI) to both read and send mail. Super useful if you need to send automated mail (eg. welcome to corp, ops notification, etc.)
Judging by how broken some of gate’s features are putting one’s faith in CCP may be inadvisable. For extra giggles go poke through some of the SDE data and observe how they don’t seem to care if the same field is encoded as an int in one record and as a float in others.