I have my own opinion about the difference and would request other tea
lovers to share the idea.

No offence with big tea companies, but I have repented in the past for
buying teas in caddies etc. One day it so happened that the loose tea
which my friend sent was of the same grade as that of the caddy that I
had bought (I won't mention the garden name or the tea caddy company) -
yes it was from the same garden and grade too was the same, but guess
what, the loose tea which my friend had sent was fresh and of superior
quality. It was "the tea" for me and I had to temporarily push the
caddy aside. I don't know what had actually gone into the caddy and for
how long had it been there.

Well there always requires an excuse for doubt and you start doubting
your whole life unless convinced - thats what happened to me.