I've been involved in debugging a bug in a software that occurred on Kubernetes cluster at the client site but couldn't be reproduced locally. Reproducing that is so much harder than a similar software installation. You have so many moving parts that it's pretty much impossible to create a test cluster with the same properties.
Also, with SaaS you can get access to log files, if it's installed on prem that can be heavily restricted by regulation.
Also, with SaaS you can get access to log files, if it's installed on prem that can be heavily restricted by regulation.