Bitcoin As Legal Tender?


As there are few countries that have put BTC as legal tender?
What does this mean for the system?
Does this make BTC more centralized?
Is making BTC legal tender a benefit?
If say all the countries in the world did this? Could BTC be more controlled and centralized?
Or would it stay decentralized?
Is making it Legal Tender just a way to offer acceptance. As a way for the government to seem friendly and let the people have better access to their own financial means?
Explain this better please?