better keep and save it so it will stay safe. when you invest it, there's a lot of risk , if you're unlucky , you'll end up losing all your money.
Not if you know what you're doing before running into investment. There are a bunch of options that don't have that much of a risk to experienced ones, but
it's true that risk grows proportionally to gains, so it's best not to be greedy when choosing an investment.
I would always choose investment over pure on holding and stashing, not only does it's likely to make a profit, but it's dynamical and interesting as well.