Sure, but when it is for things like "reimbursements, documentation and reporting, gathering and presenting business data. That sort of thing.", I'm not really

Sure, but when it is for things like "reimbursements, documentation and reporting, gathering and presenting business data. That sort of thing.", I'm not really sure offline is that big a requirement, or that there are that many major assets. Even so, your mobile browser should be able to cache CSS and hero images.