Very cool. I've done plenty of work supporting non-technical users who primarily interact with spreadsheets. This would definitely make my life easier.
Is it going to be cloud-only, or are you planning on making a desktop app? If it's cloud-only, you can grab some (hopefully many) Google Sheets users, but most Excel users will probably pass.
To answer your question, it's cloud-only -- we wanted to build Neptyne as a collaborative platform where teams of programmers and non-programmer types could get things done together. I think you're right in that this will mean it doesn't work for a certain class of user, but for now at least, we're focused on Neptyne as a web app.
Is it going to be cloud-only, or are you planning on making a desktop app? If it's cloud-only, you can grab some (hopefully many) Google Sheets users, but most Excel users will probably pass.