The product is great. But you guys will need to launch a fully feature rich desktop client, which can sync with the cloud.
Else its the same thing mentioned in the previous comments. You would build a web app with 5% the features of excel, and the moment somebody reaches use case that can't be solved with your tool, they will have to switch to excel. If they have switch every second time they use your product. They might as well do all their work in Excel to begin with.
You have to be feature compliant with excel and you can't do that on a web app alone.
Else its the same thing mentioned in the previous comments. You would build a web app with 5% the features of excel, and the moment somebody reaches use case that can't be solved with your tool, they will have to switch to excel. If they have switch every second time they use your product. They might as well do all their work in Excel to begin with.
You have to be feature compliant with excel and you can't do that on a web app alone.