It was a price problem. While there is a surprising viewer that "I did not know!" On this fact, there seems to be a lot of fans who know that "it is a setting from a long time ago."
In addition, although it is set as "price problem" in the setting of the work, various opinions are gathered that "There really is such a reason".
It is a setting to answer consistently with the voice "Why do not you use that tool?" "You can use the tools at that time here", surely, surely.
Surely Takeko is not rechargeable, it should have been used up. You can also explain that there are similar tools with different effects because they are "disposable."
Professor Fujiko F. Fujio said that "two thirds of secret tools are disposable." It is a device to not destroy children's dreams. If you continue the work for a long time, useful goods such as "secret tool" may cause inconsistency.
