You do know that Bit Locker can be defeated right?
A researcher disclosed a trivial Windows authentication bypass that puts data on BitLocker-encrypted laptops at risk.
www.pcworld.com
There's more examples. I hate to say it, but the problem is if someone has access to your computer and have the skills to actually boot into your account? Yeah, they'll eventually find a way to undo anything you've done to defeat them. It's pretty much a given.
I'm not saying don't encrypt your files if it makes you feel safer. Me I don't keep anything really important on mobile or removeable devices, period. It's too easy to lose a thumb drive or laptop, etc, or have them stolen. But it's one thing for you to make a choice, quite another to suggest it's the only choice.
Fact is M$ has a proven track record of doing things in it's own best interest over those of end users. If I was going to encrypt any files I'd go FOSS over a proprietary system. Like VeraCrypt.
https://en.wikipedia.org/wiki/VeraCrypt
When you really need to keep your files safe and secure, you need encryption. We’ve covered the basics before, and even rounded up your favorite encryption tools, but today we’re putting two of the most popular options for Windows head to head to see which one is the best at keeping your...
lifehacker.com
But to be honest while I use things like malware scanners, I'm well aware that the only really safe computer is one you don't use. And is unplugged, kept in a bank vault... Everything is vulnerable to one extent or another. IMHO relying on hardware/software solutions which can be compromised is a poor second to being security aware of how your actions effect things. Common sense is your best defense as far as I'm concerned.