We have hundreds of developers maintaining their own Jenkins jobs on a central server. We can reasonably expect them to choose whether to hit a checkbox. We cannot expect them to learn Groovy on top of their other responsibilities.
How could it not be a good idea for the plugin to handle this natively? If the plugin handles it natively, with a checkbox as suggested by Christian, then admins have a choice of using the native implementation if it works for them. They also still have the option of using Groovy if they love lots of repeated code in each of their Jenkins jobs. Without native support in the plugin, there are no options.