But you must also look at the fact that making it out of paper means you have to use one of the modifier for the EU upgrade. Not all tools benefit from it especially on tier 2 tools. For example, a hammer requires 2 plates, 1 head and 1 rod. The head and plates are added together and then averaged out to determine it's mining speed (durability not taken into consideration since we're going to use an EU upgrade anyway), so you will not want to use paper for those 3 parts and that leaves you with the rod. That only gives you one additional modifier which is going to be used on the EU upgrade.I don't like tools with limited durability either. However when you are discussing the balancing factors of durability (i.e. low durability on paper parts), you should look at the worst offender in that regard first, which in my opinion is the complete removal of that balancing factor.
Essentially what this means is that, you are trading repair fees for power bills.