Eli5. Why are different fretted instruments (guitar, mandolin, banjo, etc) tuned differently? Wouldn’t it be easier if they all were the same?

Question

Eli5. Why are different fretted instruments (guitar, mandolin, banjo, etc) tuned differently? Wouldn’t it be easier if they all were the same?

In: Other

Answer 1

Easier for whom and easier for what purpose?