The big advantage of the job DSL plugin is that if you have many similar repos, you don't just treat them all the same with multiple copies of the same Jenkinsfile, you actually can build the jobs from the same source, inheritance-style.
There could be some reasons not to do this, but if you have 100 jobs and 20 or more of them are mostly identical in form except for some parameter, it's a better strategy than multiple Jenkinsfile.
But then again if your Jenkinsfile isn't changing, it might not matter.
The big advantage of the job DSL plugin is that if you have many similar repos, you don't just treat them all the same with multiple copies of the same Jenkinsfile, you actually can build the jobs from the same source, inheritance-style.
There could be some reasons not to do this, but if you have 100 jobs and 20 or more of them are mostly identical in form except for some parameter, it's a better strategy than multiple Jenkinsfile.
But then again if your Jenkinsfile isn't changing, it might not matter.