Excellent at marketing, indifferent to mortgages
HubSpot is very good at what it is for. Email, sequences, list management, landing pages and reporting are mature, well designed and pleasant to use, and a brokerage running HubSpot for marketing is not making a mistake.
A general-purpose CRM has no concept of a mortgage deal, a lender, a condition, a maturity date or a commission split. You can model all of it with custom objects and fields, and plenty of brokerages have. What you are then maintaining is a bespoke mortgage system on someone else's platform, and the maintenance does not end.
The distinction worth holding is between the front of the funnel and the operation behind it. HubSpot is strong at the former and has nothing to say about the latter.