I know I said I was done with this discussion damn like 150 pages back or so, but, FFS...
What you, I, or anyone here think of the state of the cloud is irrelevant. The fact of the matter is Microsoft believes it's the Next Big Thing™ and have been massively promoting it for the last two years. xCloud has been a major development talking point. Spencer and others in the Xbox brand have pontificated at length about cloud gaming being a primary future focus for the brand. You'll note they've only shut up about it recently because CMA used it against them.
CMA looked at such statements, along with all the evidence they were given, and came to the conclusion that, if allowed to acquire ABK, it would give Microsoft an almost insurmountable lead in the (yes, still emerging and not-yet-here) cloud gaming market. They would have the infrastructure, the branding, the marketing, and the game library to make it next to impossible for their nearest competitors in the space, Amazon and Google, to ever be competitive. All the 'agreements' they were inking were just for show, with virtually all of the profits from the games going to Microsoft themselves.
The European Commission had the same reservations. The only difference is where the CMA decided to preemptively prevent such a future from happening, the EC decided to take Microsoft's proposed remedies with the prospect of hefty fines when/if they violated them.
I prefer CMA's approach because we've seen repeatedly that the threat of big dollar fines rarely, if ever, changes market balance once power has been consolidated.