Yarrow exists because of one specific problem: screening and hiring staff while juggling more than one client and more than one job req at the same time.
Most systems are good at one of those. Applicant trackers handle candidates and treat clients as an afterthought. Sales CRMs handle clients and know nothing about a pipeline. Agencies end up running both, plus a spreadsheet to reconcile them.
Yarrow is the whole desk in one system. Candidate to submission, client to contract, placement to margin.