Some of my most valuable experiences stemmed from just throwing myself in on the deep end instead of waiting to analyze all the implications. But at the same time those experiences were terribly _hard_, and carried a great deal of risk. E.g. my first company was an ISP. Started it with some friends at 19. Knew nothing about running a business or about setting up a large scale WAN, or about accounting, or sales, or configuring Linux servers. A year later I'd had hard, brutal and effective lessons in all of that and more.
If I'd spent time carefully trying to figure out the risks and implications beforehand, I doubt I'd have started that company. It didn't make me wealthy, but it was definitively worth it in terms of what I learned, and the connections I made also led directly to my next job and overall it has been pretty vital to my career.
On the other hand, there are many situations where not stepping back and being careful and considered and chasing down the implications up-front would've had disastrous consequences.
The problem isn't being cautious, if you know when not to be, but not taking action. Being cautious because you want to chase down and understand the implications is very different from being timid about addressing weaknesses in your knowledge. Whether you address those weaknesses with research or by trying is less important than avoiding paralysis.
It's not a universal correlation, but I've generally noticed junior and less knowledgeable people (graduate students, early-career professors, etc.) to be much more brash, confident, and even aggressive in that sense than accomplished researchers, though there is a bit of an inverted-U curve (undergraduates and 1st-year graduate students tend to be very timid). Of the people I've met professionally, probably the most humble, and least willing to make strong statements without thinking them over and later offering a tentative opinion with caveats, was Bob Moog, who is also probably the smartest and most accomplished person I've met professionally.