Having a replaceable battery kind of undermines its potential as an anti-theft device, so it's not true that there wouldn't be any be benefit at all to having a non-replaceable battery.
Co-advisors should be on an equal footing in terms of the power dynamics. They can discuss amongst themselves any advice that they feel might be obstructed by biases and should be able to do so frankly. If others in the advisor group agree on the advice, then they can then present their advice as a group rather than as an individual to the person they are advising.
At that point it doesn't matter who the person is breaking the news. The advice comes from a group of diverse people and is then far more defensible against accusations of sexism, racism, etc..
Perhaps male advisers who are worried about such things could ensure they have a female co-adviser they can have frank conversations with. Why should it fall on one investor to tell the founder that they shouldn't be CEO?
This article is actually a very strong argument for diversity in boards.
Creating travel planning software may well be a bad idea, but I find the reason he gives is really weak. It boils down to:
People in America don't plan travel often enough.
If that was the reason, then almost any travel startup is non-worthy. This is definitely a problem, but it's more to do with the difficulty of ranking a travel planning site in Google which is where people who don't travel often usually begin their planning. This is why SEO is so critical to any travel website.
It also conveniently ignores the rest of the world as a market. People outside the US do in fact travel far more often and more elaborately and ignoring them in the equation just boggles my mind.
My experience from this is that people do have very different expectations of how a travel planning tool should work. So the earlier comment that it faces the same challenges as to-do apps, etc.. rings very true to me.