How important is content marketing in SaaS business?

That highly depends on the market you are trying to reach. If it's a B2C SaaS it highly helps. If its B2B, clients in that market generally do not search for solutions. Or, if your SaaS include or collaborate with existing products like excel, content marketing helps.

I think so - high-quality content establishes you as an authority in the field and actually helps your customers.