You have to consider all marketing in this discussion – not just SEO.
A short catchy name is likely not as good as a hyphenated one as far as SEO goes, unless you can afford gambling.com
A short catchy name is good for branding, and that is a totally different business model from what most portals do now.
Branding takes time and money – and you better have lots of at least one of those two factors.
After over 2 years of branding GamesandCasino gets about 60% of visits from bookmarks and people typing the name in. So I still need the engines, but not so much. It’s not even such a short name, but people can remember it.
It is a lot easier and faster to make $ with an seo site than a branded one. Of course you optimize the branded one also. Just that the name will be less helpful.
Take casinomeister. Not a seo word, except for the branding.
They are both valid ways of marketing online, but they require a different approach and branding is certainly not an easy or fast way to go.