Answer:
Because her services as a nurse, cook, spy and scout were not documented compensation was hard to get. All Tubman had received was $200 for 3 years of service. all the doucumenus lacked official sources
Explanation:
The main thing was electricity
Filial piety is a Chinese concept (respect for elders) so I wonder whether you mean in China, but I'll answer generally:
Respect for those who have been there before us, and learning can give us invaluable information about what has worked in the past and what hasn't, which is a good input into a good government. Also respect for elders is also a good basis for a harmonious society.