[2020] Is there any official answer about why Echo Ult disallows you to change your hero during it?

Has someone from Blizzard officially said if it's an ability they intentionally gave her or if it was given out of necessity because of some tech reasons like a lot of people were guessing?

It just feels a bit pointless and frustrating. Echo's kit is already so strong, it doesn't feel like she needs this ability but if it is a technical reason it'll be understandable.

Edit : Jeff confirmed it in comments, it's a technical limitation. "this is a technical limitation related to how many heroes can be loaded into memory at one time."