Reg-exps aren’t hard. They’re covered in ungrad courses on state machines. Not understanding the tool you are using can be dangerous. Letting a wizard handle it for you means you no longer understand what the code is doing. You end up doing cargo-cult programming.
What’s hard is using reg-exps to deal with fuzzy real-world data.
Your phone number example:
"^\(*\d{3}\)*( |-)*\d{3}( |-)*\d{4}$"
fails when confronted with a number with an international dialing prefix, or any non-US number.
Your domain example
"[^\\]+$"
fails when confronted with the e-mail address form (user@domain) or a forward-slash form (user/domain)
It’s dealing with all this that makes reg-exps hard. It’s why the RFC-822 parser is so huge. E-mail addresses aren’t always foo@bar.com.