By having both options it both gives users choice and lets the market decide which they prefer.
Absolutely!
And different tribes can adopt different approaches.
This is exactly why centralized governance at the tribe level does not bother me. The decentralization happens at the 'consumer' level.
If I don't like the way the 'tribe CEO' is running things, I can invest my time and treasure in a different tribe -- I vote with my sneakers!
And not only that -- if I disagree with the way all the other tribes are being managed and if I'm an adventurous sort, I can go out and create my own tribe.