The only surprising bit for me was the dividends. Most terms sheets I've seen don't require the 6% dividend. Seems weird.
I wonder if this is more of a protection against the board deciding on a dividend when it is in the best interest in the near term for the company to keep money in the bank. So defining 6% might mean "this company has so much cash that they can return a 6% dividend without harming the long-term potential". Perhaps if you aren't able to return 6%, you aren't ready to return a dividend at all?
It's relatively rare for venture backed startups to issue ordinary course dividends anyway (for the reason you stated, funding development/growth is typically seen as a better use of company cash to try to get to a big exit or IPO, etc.).