Recruitment is the only sector on this site where you are selling to both sides at once. A client vacancy is worthless without candidates and a strong candidate is worthless without a live role, so the system has to hold both and keep them connected.
Most agencies end up with candidates in one place, clients in another, and the matching happening in someone's head. That works while the consultant who holds it stays. It stops working the moment they are on holiday, overloaded or leave.
The second problem is slower and more expensive. Candidate records accumulate for years with no consent record and no retention rule attached, which is a UK GDPR exposure sitting quietly in your database.