Atleast there are two important reasons that make walmart interested in cryptocurrency.
1. To reduce interchange fees
2. To enchances cross border remittance
In 2013 wallmart paid roughly $3 billion in interchanges fee. It seems that wallmart has good reason to find way out for it's problems by using cryptocurrency. I think instead of still using the traditional way of doing transaction we better use a more modern way that is certainly better. Bitcoin price will rise because when wallmart pay it's employee using cryptocurrency it will create demand for bitcoin. It can be good sentiment for bitcoin price.