In older versions of ERPNext there was only a Sales Invoice. The POS Invoice is something new.
Why does it exist? What makes it different form the Sales Invoice?
When in Sales Invoice, if I click on the check box to use POS payment then what am I creating? A Sales Invoice or a POS Invoice?
Why the difference? Why do we now need the 2 different types of invoice?
BKM
POS invoice has been created to sync the data with ERP faster. It does not run as many checks as in Sales invoice. It does not have any effect on accounts.
On doing closing entry sales invoices are created in background for all the open pos invoices
for your morning reading 
Hmm… Interesting that you bring this up.
If it is true that a POS Invoice has no effect on accounts, then why does POS Invoice have “Account User” role assigned to it by defaut?
Sales Invoice does not have this default role. So why is it in POS Invoice.
I noticed this today and that is exactly why I asked the question about what makes these two invoice types different. It didn’t make sense to me that a POS Invoice would require the Account User role when it is not required for a Sales Invoice.
So you have hit exactly on the reason for my question here.
What makes them different enough to warrant such extreme differences in their required role permissions?
Am I missing something here?
If the only true point of POS Invoice it to stack up pending transactions that will eventually become Sales Invoices, then why does the lesser important one need Account User role?
BKM