Theory here is that people will build apps that talk to S3. But sometimes those apps might need to run inside the perimeter and can't talk to the cloud. So rather than rewrite an app to talk to a new internal datastore, you just point it at a locally hosted Minio and you're up and running. Smart.
What kind of situations do you see this becoming a factor in? 5 or 10 years ago this was an issue with early cloud adopters. Now a days cloud providers are ramping up their DCs to be compliant and allow companies/government entities with strict policies to still onboard. Its a good strategy but not one that I see being exercised frequently enough.
There pretty much isn't anything you can do to improve their internet connections as cables to remote places are always getting dug up with week+ times to repair so you need something that can run locally for long periods. Ships have a different problem with very slow speeds that effectively means you can only transmit the absolute minimum off the ship when its out as sea (when they are at port they typically have normal internet connections to bulk dump data off on).