Could you please elaborate on whether Bizum, as a payment service, can be utilized across international borders? I'm curious to know if it offers cross-border transactions or if it's strictly limited to domestic use within its native country. It would be helpful if you could provide insights into any potential limitations or challenges related to its international applicability. Additionally, could you also discuss any alternative payment methods that might be suitable for international transactions, especially in the context of cryptocurrency and finance? Thank you for your assistance in clarifying this matter.