As long as you believe you can acquire customers for some margin less than (you project) they will pay you across their lifetime as a customer, the rational choice to to maximise your money is to spend all the money you have (and more!) on acquiring more customers.
As a result, the majority of SaaS businesses aren't profitable, and people talk mostly about MRR.
As a result, the majority of SaaS businesses aren't profitable, and people talk mostly about MRR.