What's the catch?

Sl. What is the drawback?; It sounds good, but are there any hidden problems? Sounds too good to be true. What's the catch? This looks like a good deal. What's the catch?

Common Names:

Name	Pronounced	Usage
Hills	[hilz]
Harlow	HAHR-lo	English
Noora	NO:-rah	Finnish
Kerri	KER-ee	English
Mona (2)	-	Swedish, Norwegian, Danish
Ahlberg	['ɔ:lbɜ:g]