Brother @fucho80: first of all let me congratulate you on this magnificent post that you have brought us today.

The theme you have selected, caught my attention from the first moment. I consider it a reflection of great importance that all of us should do.

Do the tribes really favor the strengthening of steem and steemit? Are they bringing a beneficial contribution to this ecosystem, or are they becoming an alternative to the STEEMIT platform?

I believe that the tribes are enhancing in an unprecedented way the benefits, capabilities and reach of Steemit.

In my opinion there is no dispersion. On the contrary, we now have a concentration of users in the areas that are really matters of interest to each one. The tribes are creating "niches" that allow an audience to concentrate and search for the publications they like. Previously, with the use of tags, finding a specific publication was very difficult, now with the tribes we can go directly to a group of creators who maintain a common theme.

As you mentioned, the tribes have their own interface very similar to the steemit interface. They also have their own tokens.
We can see these tokens as pure STEEM, in fact they are. So, we are facing a marketing of STEEM itself. This can only favor our native currency and increase its value since we are now having more investment.