Bitcoin is such a expensive and slow crypto to use for betting purposes, why do sites insist on using bitcoin only?
I would have imagined that they would prefer a quicker cheaper crypto to lure gamblers to their site. Imagine a tilted gambler trying to deposit hit last 0.5 bitcoin after losing his life savings and it taking 3 hours to get through. He would be tilt free by then

You can look for sportsBook that accept 0 confirmation deposits.Most of the casinos avoid it to prevent double spending.You can ask your favourite sportsBook to implement SegWit to solve the network issues.Also most of the sportsbooks do accept ETH or ETH based coins.You need to explore more.