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 en
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.