Default strength 2 collation vs not

Hello,

What is considered a better practice?

a) Creating a collection with the default case-insensitive collation set
VS:
b) Creating strength lv 2 collation indexes on a collection that doesn’t have them set as a default?

What are the strengths and weaknesses of any of this approaches and which one is recommended as a conventional practice for performing case-insensitive queries?

Thank you