Muse Spark may be competitive in capabilities but it’s not for serious works since Meta trains on your prompts so no ZDR, in contrast Chinese provider like Z.AI promises ZDR which is more attractive to big corps.
I do not trust any provider, US or Chinese when they say they will not train on my data. I still use these services, but I am under no illusion that any of these people are trustworthy bunch.
While I agree with you for the Muse Spark as hosted by Meta, if it will be available in open weights form for self hosting, then there are good chances that it can become quite useful.