As you've already said in your post, you want to tell people, " .... why it
would be beneficial for them to use ...." That's exactly what to do. I
believe software is just the same as selling anything else - sell the
benefits.
Benefits are relative and vary depending on the needs of the person, target
audience or market. For example, small business owners will expect something
different from their software than home users, professionals something else
and office workers something different again. So I would sell the benefits of
the software, but not the benefits as I see it, but rather the benefits for
the users, or group of users, I'm selling to.
In general, "selling benefits" need to be tangible and immediate. For
example, I could say to a small business owner that Trisquel is free of
restrictive licenses, proprietary software and formats. That's factual,
positive and beneficial but it isn't a selling benefit, because it doesn't
address a tangible and immediate need of that person.
In contrast, I could also say that Trisquel has no license fees regardless of
the number of users, and that it comes with a complete suite of office
applications at no extra charge. To a business person, those are selling
benefits, because they address real and relevant needs; the need to control
costs and avoid additional expenditure.
I hope this helps. Good luck with your venture. I'd love to know how works
out for you.