It's a beta. You're helping them test it, so them collecting usage/statistics is completely fair. If you don't want to take part in the beta testing, don't install the beta and wait for the full release (which the creator said elsewhere in the thread won't require email or data collection).
In saying that, I do think a sentence above the email field saying "By taking part in this beta, you're helping us collect data to improve the product for final release, which will not require your email address or do data collection unless opting in" or some such.
