It's none of the said reasons.
But there is also another reason when you think of it.
In order to make an Event as legit (or even legal) as possible without having the real thing, you would have to reconstruct the whole process of what actually happens when you load an official Event.
As a perfectionist I feel kinda unsatisfied sometimes with the idea of "injection" and make no mistake about it, I think it's a great thing and we did a great job. Or I should better say sukoku did a great job.
But we gotta admit that it could be better and I mean not only in the case of Mystery Events but also Mystery Gifts. I was told very often that in order to make it really legal or legit you would have to load the Event via Mystery Event as it should be. I couldn't understand it first, because to me injection looked fine, but it's true that Injection is kinda like a "shortcut" to get the result you want to have at the end without having to deal with the whole process of actually receiving the Event in real time while playing as it was meant to be...
Now technically spoken and I gotta say this... I'm not even sure if everything that changes in an save file in an injection compared to downloading an Event gives the exact same result. We have some before and after save files, but I haven't done any documentation about them since I was extremely busy during the time and I don't know if suloku has done it, I think he should have done it, but I don't know.
I know I said this before but even better and more empirical would be to disassemble the Event itself rather than just documenting. Now an European Eon Ticket Cartridge has been leaked but is out of reach unfortunately.
Luckily we still have the US Eon Ticket e-Card and let's assume when you use it with the e-Reader, it should be almost identical to what's going on when you use a Distribution Rom.
We are at least lucky that its packages have been documentated already: http://forums.glitchcity.info/index.php?topic=7114.0
This brings me back to what I'm actually trying to do.
And I'm not sure if I would personally bother to look more into it for only one Event, so that's why I was trying to make this e-Card right away with what's been documented already.
I don't get it to work so I think maybe there are some undocumented differences when it comes to Japanese e-Cards... who knows...