It's easy to get yourself as a founder into a situation where you're trading fundamentals for next-round narrative, and a lot of times that's that can be the deathknell.
The difference between those two values represents a gap that has to be closed before you're on steady ground, and the gap widens at a higher-than-normal rate because of the growth expectations of the VC money.
Anyway, that's what it looks like to this complete outsider. Companies full of very capable people, pushed to do desperate things, and to do those things quickly. And, like the churn of leveraged Wall Street finance, there are plenty of people who live for the froth of it all.
Also, many startup investments use debt instruments like convertible notes instead of direct equity purchases.
There's no free lunch, but taking investment can let you achieve great things and build incredible communities. Just make sure you talk with founder/banker/lawyer friends who have seen the dark side of things, and use their experiences as armor.