The presidios faced many challenges such as food and security of its people and struggle to maintain their control from the natives people and save themselves from native people that lives around them because the Spanish comes and captured their lands. Spanish soldier defend the newly captured territories and take on such a difficult job for their country's welfare, prosperity and for expanding influence of their country.
Blitzkrieg was so fast that the enemy didn't have time to prepare, whereas in WW1 where they fought in trenches, they would have to cross no-mans land and the enemy could see them coming