But that's not as "sticky" as software. If you decide to cut costs next year on training because its non-essential, the revenue gets slashed. If I still need to procure stuff, I'm not going to shut off my procurement software to cut costs.
On the flip-side, if cost-cutting becomes important, a company may decide to invest in current employees skills in lieu of hiring new external employees. Any software that isn't mission-critical faces high risk in a cost-cutting environment.
My take on it is that B2B customers are difficult and expensive to acquire and Adecco has a relationship with 100,000 leads. Seems like a good acquisition to me.