Because you can just use a low-level tool, apply some magick like Regrowth spell or Oberon's spell, then use it to harvest higher-tier materials.
Not clear if this is intended. it makes a lot of intermediate tools obsolete because you don't need to craft them to harvest higher-tier resources.
Suggestion:
The Tier of a tool is based on the Tier of the tech design. When a low-Tier tool is used on a higher-tier node, the durability damage increases dramatically.
So a low-tech tool can still be used to harvest high-tier nodes if crafted with high-tier materials, but the durability cost still makes it wear out quickly because low-tech tool designs have lower durability. This encourages players to upgrade to better tool designs (higher-Tier tools).
Oberon's Bounty breaks a tool if used on a higher-tier node.
