Dunno if you're referring to a search warrant or arrest warrant; I'll assume the latter.

Broadly speaking, arrest warrants are issued because many suspects flee and hide instead of choosing to face justice, so the police has to arrest them to prevent that from happening.

In cases where the suspect is deemed unlikely to flee (or be unsuccessful at hiding) the justice system sometimes allows them to surrender on their own to face arraignment.

Additional factors: Was the crime violent, or white collar? Is the person sufficiently high-profile enough that offering a voluntary surrender is (politically and socially) preferable to arresting them at their home?