But where do we draw the line? Should they be buying cheap Lenovo laptops and second hand furniture for their office too, out of fiduciary duties? I don't mean to be facetious, but my point is that on some level the investors is investing in the company (or more accurately its leadership) and trust they will do the "right" thing... its a heuristics thing - does sweating the details on things that other people may find irrelevant make it so? Not necessarily. Building the brand, culture, product the way that the company deems it best is kind of what its about no? (validated by paying customers, company growth and whatever metrics the VCs and others are looking at).
Whilst "what a VC-funded startup should be burning money on" is something that the investors should have input on, I don't think random people on the Internet get to be the gatekeepers for what a company is allowed to do with their investors' money.
It's not about being allowed or disallowed. It's about having priorities as a startup. And every random person on the Internet has the right to say that his priorities at this stage would be very different.