My experience from being a part of payments, e-banking, mobile, e-id etc development work has been that one should start with services that "all people" (Ms Same Guy in her private, entreprenaur and employee roles) use "all the time".
Then use the same tool (habit, trust, investment etc created) for services needed less frequently by all or many. Try to save
what few need seldom to the last moment.
This could be likened to a broad but narrowing staircase leading upwards to a combined value that cannot be achieved fast, at low cost, in a user friendly etc in any other way - if at all - in this information overflow age
where the plastic brain has reacted by next-to-eliminating attention span..
With this logic we moved from payments to e-banking to e-invoicing to e-salary to e-id to e-signing and so forth - with a multitude of smaller innovations on both sides of the mainstream.
Now - only - are we moving to the top priority of accountants (who are winning the fight against paper and PDFs with structured e-invoicing) the POSreceipts - desparately needed for automating the rest of both SME/large enterprise accounting, VAT reporting
etc and naturally also for private accounting. Thinking of how astronomically many lines their are in these and how these can easily be standardised using the
local e-invoicing standard makes one wonder why this has taken so long.
Exciting times for new ecosystems - but we need to work together for the standards and the needed rulebooks.