Touchbar is irrelevant, but there's some merit in getting the latest hardware (as in processor, memory). I am running a 2012 Macbook pro with i7 processor and it still runs very, very smooth. I've replaced the battery once ($80 from ebay) and will gladly replace the battery again if it goes again. This laptop can last me another 3-4 years EASY, and will be my longest running computer by quite a margin. I think previously, my longest lasting Windows laptop was ~ 5 years old, and it was really slow at the end of the 5 years I couldn't wait to get rid of it. Here I'm on my 5th year of my MBP and it handles everything I throw at it - including video processing, without missing a beat.
Whenever I have to upgrade my laptop again, I am getting myself another MBP. My wife has a MBA, also on its 5th year, and it is also going strong like day 1. And I wasn't a believer of Mac at all before I got these 2 Mac's.