As always with standards EPC QR is not only one in europe. In Czechia for example the QR codes are extremely popular but since they were introduced before EPC QR they are in SPAYD format. I think they became popular because instant payments between czech banks were introduced sooner than in the SEPA network.

Maybe that's why they were separate formats BUT afaik even SPAYD uses IBAN account numbers. So I have no idea why there are both of these, they are just syntax. The main difference being that SPAYD is key:value pair separated by * and EPC is fixed position, line delimited. I personally think SPAYD is more human readable and extensible BUT i guess less efficient. Not that it would matter i would prefer the one that's universal.