Most eggshells are discarded by industry, not households, so if this process captures them at a lower cost than landfill the industrial egg users will benefit. This is not unlike the companies that collect wast oil from restaurants and recycle it into fuel.
All the same, this article doesn’t have enough detail to determine whether the process is worthwhile.
“Most eggshells are discarded by industry, not households,”
Regardless, the practical means to their capture does not exist and will not be accepted. Its a joke and industry is not going to engage in it with any purpose from which the development of the means will be looked for. You cannot pay industry enough to produce and use the means to recycle eggshells and if you decreed a price they would accept then the end-product users of the resulting hydrogen could not afford it.