I can agree that windows can be the path of least resistance because of legacy business softwares. But please don't even start to argue that windows is more easy to use than an iPad.

For a lot of professional things windows (Or Mac or Linux) is better. For data entry a tablet is a real pain. I wouldn't want to do accounting on an iPad for example.

How is doing small business accounting on an iPad, with a keyboard, any different that doing small business accounting on a Surface? You tap on the screen where you want to put data and type. Also, when using FreshBooks, which is what my comment was about, once you set up your customers, line items, and rates, creating an invoice involves about five taps and maybe typing in the number of hours/quantity, if it differs from the default of 1. That's it. I'm not sure how Windows could possibly make that any easier.

How does "going Windows" make doing small business accounting easier?

You have a lot of mature software available for that task.