> I'm left wondering what the catch is / why it's cheaper and faster.

So, while this is the first time I've heard of ubicloud, I use gha extensively.

Abd frankly, I think it's just because Github has a crazy markup on their actions compute over the raw compute. Taking a quick look, it appears that their base rate is like $0.008 per-minute!! That's a rate that wouldn't look crazy out of line with EC2's hourly rate.

I've worked on projects where we saved significant money, and improved build times just by launching a single EC2 instance and connecting it to Actions.