The crafting grind isn’t easy at times we find ourselves with a surplus of azoth and/or mods (for perks).
If the crafter adds those to the creation, it would be nice to have more than the flat xp for that attempt. Doing so incentivizes item sinks (azoth/mods) and gives a minor boost to those grinding through crafting.
Another route to the same end would be that rare/epic/legendary rolls of an attempt should earn a multiple of the base xp.