The ease. I had to start creating projections for the funding process and was dreading it. I found this on a Saturday morning and by early afternoon I had yearly/monthly numbers for 5 years P&L, Balance Sheet, Income Statement and Cashflow. Keep in mind this included time getting used to the software and answering questions outside of the software itself (ie units sold per month).
But these weren't just useless numbers, they were based on results of answering questions about the business. And they did a wonderful job making it simple. For example, you add a new product, the revenue type (one time, recurring, unit, etc), units sold by month, price and churn. And because you won't get it right the first time, it makes adjusting the estimated units by month easy.
Similar entry for all your expenses such as employees (by department/position/start date/salary) and other expenses.
So now that you've entered all this - it then automatically becomes available in your business plan. The business plan is easy too as they put all the typical sections (problem, market size, team, etc) in there but it's easily customizable as well.
And finally, you can invite people to edit or just view it as I've done for investors. So investors groups would like you to put your info into their own "room", but I've just given them access here so that I don't have to keep multiple versions up to date.
I tell every startup I meet and all the local startup agencies to have their startups use it too.