One commercial advantage of business accounts, is they tend to be fee-based, so these accounts will be more profitable for Starling to be offering.
More money in Starling’s coffers means more money available to continue the development of both strands and to continue expansion plans, like taking on more CS agents.
I agree that spreading yourself too thin as a company is never good (I am self-employed and learnt that the hard way through severe lack of sleep!) BUT introducing new features and products that are suitably similar to existing ones that development can be shared which increasing revenue is, in my opinion, a good an natural place to be looking.
We don’t know much about Starling plans for business yet but we do know that they are targeting sole traders and micro businesses. I am a sole trader, and in all honesty I could very easily run my business on the current starling personal platform if I wanted to, obviously I cant have multiple accounts so it’s a no-go, but very little, in my opinion, needs to be tweaked before they can offer a good sole trader business experience.