Yes, betting is off-chain, what do you mean by "betting will be so low" ?
Thanks for your input
I said because you said the seeds will be on the other server. So in every bet user will make a HTTP request to remote server to get his seed? This should slowed the betting.
We have developed a specific solution to this issue : a stand-alone roll server, to be deployed on a machine managed by large investors, or an highly trusted third party.