This is a great question and would appreciate the clarifications on why set lab decided to issue an index token rather than a set protocol token. My first impression is maybe set protocol would like to stay as a for profit private organization while index protocol is the community version of it. But I do see the possibilities of it having conflicting interest down the road on how the fees are being distributed, on the percentage allocated to set protocol and index token holders.
And I am guessing we are in default going to use set protocol as the issuing platform. It might be a good idea to set in stone what are the expected fees would be.
I think we can view index protocol as a subsidiary of set protocol where set protocol and defi pulse is holding 30% shares. This kind of structure is quite common even in traditional industries.