Does a faster computer truly equate to an increase in productivity? How old is your work laptop?
I use a 6 year old Thinkpad and a 4 year old Macbook. If I need to compile something big, I ssh into a build server.
The mid-2015 and earlier Macbooks are better anyways.
Like everything it depends on what you are doing. If you are doing frontend work that requires you to have 3 browsers open at a time + an Electron-based editor + a dev server you are going to need a lot more than someone who is writing low-level C code in Vim.
As an aside: newer =/= better.
If we're talking a two-year-old Macbook vs the latest Macbook, I don't think there's much of a noticeable difference in productivity
Recently I got a brand new XPS 15 with the most RAM and fastest CPU. The storage was M.2. It felt sluggish and I returned it.
Laptops are weird and hard to shop for.
It is fast, but a tank. Has that Optimus combined Intel, nVidia graphics system, pain in the ass edition. Otherwise, awesome machine.