Those who primarily use iOS and Android mobile devices can probably stick with free apps. The subscription will appeal to people who use Office apps on traditional Windows or Mac computers or Windows tablets, such as the Surface Pro 3.
It's a smart move by Microsoft, but it makes me wonder whether you really need a subscription, which starts at $70 a year. The company now offers Word, Excel and others at no cost on most mobile devices.
Just as I was warming up to choosing a Microsoft Office 365 subscription over making a one-time software purchase, Microsoft started giving away a lot of subscription benefits for free.