I do have a site but I use it to funnel traffic to places like my LoyalFans where I can get 80% and a place where my customers can email me. That way if a customer from a lower paying site searches your cam name they can find you and when they email you you can send them to a higher percent site without risking your cam accounts by speaking to them on the site about going to a higher paying place.
Having your own payment processing is not worth it in my opinion. First of all it's not easy to get a high risk merchant account that will allow adult processing. In order to take Visa and Mastercard there is a high yearly fee (last I checked it's around 1000 each, and that is every year). Also chargebacks are a huge issue. Each chargeback you not only worked for free, you get charged a chargeback fee for each chargeback (I think t's over $50), and that's for every single transaction. If someone charges back ten videos that's $500. If your chargeback rate goes above a certain percent you lose your processor. The only way I can see it would be worth having your own adult processor is if you have a huge fanbase where you could cover all of those extra expenses. I do see some who try to get away with using a nonadult processor but they don't last long before the processor catches on and they get banned.
With that said though, it's well worth having your own site to send customers to all the places you cam, take custom video orders and sell clips and funneling them to the highest paying sites. Also, no guarantee a cam or clip sales site won't go under or ban you for some reason or traffic is better at another place and you move sites. This way your customers can always find you at your website.