I work for a MSP. Recently, i started to introduce Rundeck in my team for the following reasons.
My team has a significant amount of conventional sysadmins, mostly running linux-based servers, some kubernetes. We do use infrastructe-as-code tools, such as saltstack, have access to ci/cd platforms and various tools. However, my team has only a few people developing, most don't really know how to use git, let alone gitlab/github/etc. This results into a situation where many admins prefer doing stuff manually, instead of writing code with our infrastructure tools. Though, most would be able to write bash scripts.
In order to "crowd-source" the development of our processes I needed a tool which is easy to use, somewhat easier to create workflows, and being managable (ldap, logging, acls), and adaptable (plugins, integrations), low costs, ideally open-source. Although our infrastructure wouldn't need it since we already have capable tools, they are arguably too complex for my environment. complex in the meaning of not enough time/money to teach the majority of the team, lack of interest and motivation, etc.
My research resulted in Rundeck fitting best for my situation and requirements.
Though there were a few other contenders, since Rundeck is not the most efficient workflow engine, nor has the most integrations, biggest community, etc.