I would hesitate to call something like this a translation. The proper name chosen for these entities (which mostly have names taken from angels IIRC) happens to be Angel, but it's not like the creators are suggesting the word 使徒 means angel in any sense. They must have thought it sounded good and aligned with the angel names of the individual Angels. I believe Anno has said there was no deep reason for choosing 使徒 or the individual Angel names except that they sounded good to them, so it makes sense that the localization team would go for what they think works best.
it's not the Western localization team which choose to go with Angel btw
the Japanese original already uses the term "Angel" on computer displays the NERF staff controls etc
NGE staff probably thought the Japanese viewers wouldn't be able to recognize the term apostle and that's likely why they went with angel instead
Translation of this word in Neon Genesis: Evangelion
I've noticed that this word is translated as "angel" in Neon Genesis: Evangelion. I feel like "apostle" would have sounded cooler.