Okay… for the whole e-mail thing, if humanity has access to move people faster than light, but lack the ability to move just information faster than light, it would make sense to have a courier move the information, especially if it’s between two bodies that are sufficiently distant. For context, it takes the Mars rovers between 4 to 24 minutes to receive communications from Earth, depending on the distance between Earth and Mars, and that’s with radio, which travels at the speed of light. In addition, in cases where you’re moving large amounts of data between two locations, it could be faster to simply put the information onto a flash drive and deliver it to whoever you are sending it to. In fact, Alphabet/Google uses this method to move data internally.