use of "_" in normal mods elements

I know that for many people this is a very silly request, but it seems to me that using the underscore to organize the articles would be fine.
because, as you know in all the mods external to the program and, in fact, also the Minecraft Vanilla uses it to supplant the spaces, and then randomly, you discover that this sign can only be used in duplicate (or copied) mod elements , since if you try to use a new mod element it will not work, this sign can also be used for the division of classes or objects and elements, for example:

iron_ingot
iron_sword

It is marked "type" and then the "subtype", here our "type" is the "iron" and our "subtype" is the "sword" or the "ingot", it is quite simple to use and I found it interesting to see that It can only be applied to duplicate mod elements and not to newly created elements.

for me it would be great to use this and so order the mod elements better.

I don't know if anyone will see this, but it's just an idea (very simple and for people some bit useless)

pt: sorry for my bad english, I'm not very good at this language