It tracks IP addresses in order to know if multiple accounts are being operated via the same device. However, it may be that you have a family member who shares the same IP address and also wants to have a Bet365 account. A VPN lets you do this because you can change your IP address.
Bet365 is an online gambling company offering sports betting and casino type games. In addition to the company headquarters in Stoke-on-Trent, Bet365 have further offices in Manchester, Gibraltar, Malta, Bulgaria and Australia.