So Friend I come across many posts in which I find users are not using the tribe tags even when content can be fit for that tribe.

I noticed this when I saw PAL got pumped and I found there are lot of users that do not use PAL tag when almost everything can fit in it and I experienced the same for Neoxian.
It also look kind of stupid when user are not using Leo interface for their financial posts and suffer 10% penalty.
Okay all of these looks very small steps and I think if you see the effect on a single post then it might look insignificant but when it will be done for long period of time then it might become significant.
You never know if a Leo whale did not voted for you because you did not used the native interface. Even you got upvoted then paying 10% penalty for such a large vote will look significant.
I feel you should you use all relevant and permissible tribe to gain more exposure and some nice tribe tokens.
You never know what can skyrocket on next bull run.