Can AliPay HK pay in China?

Could you please clarify if AliPay HK, a digital wallet service offered in Hong Kong, is capable of facilitating payments within the mainland China? It's essential to understand the cross-border capabilities of this payment method, especially for those who frequently travel or conduct business across these regions. Is there any specific restriction or requirement that users need to be aware of when using AliPay HK for payments in China? Additionally, are there any alternative payment methods that are more suitable for transactions in China?