> I don't know how well this works in practice, As soon as you don't control the whole thing end-to-end, i.e. from the user entering the data to printing it on

> I don't know how well this works in practice, As soon as you don't control the whole thing end-to-end, i.e. from the user entering the data to printing it on an envelope: it won't work at all. It would require every program in the whole chain to accept this "big blob", which is simply not going to happen.