The main purpose of a builder is to simply build maps (they obviously do more than that lol), staff members are much more powerful and have different duties - the helper / builder application is also very different. We obviously wouldn’t let some staff member build a dirt house then upload it as a MM map or whatever, the maps are checked by builders / Vertx before they’re published into the server.
While a staff members main purpose isn’t to create maps, if we have the free time then I don’t think there’s much harm in it, even a builder could try helping out or apply for staff, if they really wanted to. The build team captain / co-captain (I’m not 100% sure about the co-captain cause like, I forgot lol - but I’m 99% sure they can

) have staff perms, but they’re still able to build maps.
I’m friends with like, pretty much everybody on the staff team, including the builders, I’m fairly certain none of them even care there’s a couple staff members building maps, I’ve even built a map with one before. They definitely do a lot more (building wise) whenever it comes to maps, like the whole server has hundreds of maps and 95% of them are most likely made by builders.