I went through that map, it seems most of the countries out there have been leninent about crypto but have not considered them as legal tender, at least we are making some sort of progress here.
The Premier League is the most watchable football league and crypto casinos promote the least-ranking football clubs in the Premier League. I think this is a cost-effective method to promote a casino, they increase their awareness, especially when their club plays against top teams like Manchester City, Liverpool and etc...
Indeed the EPL is the most popular soccer league out there both in the UK and outside UK, many other countries have their leagues but they are popular inside their country and not outside it. EPL fans are present all over India and the celebrations here are often similar to out home country cricket matches.
Rollbit and many other crypto casinos have an exclusive, British version aimed at the British population. Rollbit operates as Rollbit.co.uk in Great Britain and as far as I know, they don't accept cryptocurrencies on their British website but via this advertisement, they'll attract many people worldwide to their major, rollbit.com website.
It is a good marketing decision like I said, both their UK site and original crypto casino site are going to get more traffic during the soccer seasons.