When you're a new business owner, everything seems a little scary and overwhelming. It's hard to take charge and assert yourself when you don't have the experience to fall back upon.
And if you're not confident, your potential customers won't be confident in you.
How do you become self-assured without having experience as a business owner?
If your copy is talking about your competition, you're giving potential customers a reason to check them out. You're giving them the name of someone else they can buy from. You might be introducing them to your competition when they didn't know they even existed!