Yes it is right.
My confusion was with legacy 802.11n APs. With legacy 802.11n APs, you could enable spectrum load balancing and have ClientMatch disabled:
Spectrum load balancing is disabled by default, and can be enabled for 2.4G traffic through an 802.11g profile or for 5G traffic through an 802.11a RF management profile. The spectrum load balancing feature also requires that the 802.11a or 802.11g RF management profiles reference an ARM profile with ARM scanning enabled.
Although that was not recommended:
ClientMatch is recommended over the legacy bandsteering and spectrum load balancing features, which, unlike client match, do not trigger AP changes for clients already associated to an AP.
When you enable client match on 802.11n-capable devices, the client match feature overrides any settings configured for the legacy bandsteering, station handoff assist or load balancing features.
Regards,
Julián