Interesting article on it by Michael Atherton here:
https://www.thetimes.com/sport/crick...rton-t0506qst2 (Non-paywall version here:
https://archive.ph/ercSr)
I don't know the ins and outs of the relationship but surely Glamorgan would benefit from any financial growth and success that Welsh Fire have, and the owners seem very bullish about that. Although he does acknowledge some of the big barriers to Glamorgan's long-term success.
On a side note, I'd be tempted to watch a few more Welsh Fire games if they could attract the likes of Travis Head, Glenn Maxwell, and Rachin Ravindra.