If the full extent of this rule is just the logging action you have posted above then there’s not a lot of learning to do to convert this rule over to js. There are plenty of good examples here on the forum of how use logging in js rules and you can even setup the rule in the blocky editor and the see what its js output is then just modify that to include the event.channel information you want. If there’s more to the rule that you haven’t posted, then it might be a slightly steeper learning curve to get the rule into js.
There is, to my knowledge, no plan to remove the rules DSL from openhab, if you you choose to learn js for rules scripting it’s only because 1) there are some limitations to rules DSL that you can get around by using js (such as the one you have found here), 2) some more complex rules logic can occasionally be simplified by using js, 3) you just want to learn something new.
I personally, don’t hesitate to use different languages at different times; IMHO each is a tool with different strengths. Most of my rules are in js, but some are still in rules DSL and a few even in python. Some people aren’t comfortable with that kind of scattershot approach and prefer to have everything in one language. That has its advantages too.