I would have thought it would be ok too, but I'm guessing your machine has an SSD, so when it occasionally needs to use swap space you barely even notice. On a machine with a bare spinning platter drive and no fusion drive, going to swap can be awful for performance. You’ll really notice it. So most of the time everything will be fine, but now and then it will suddenly start crawling.
Also Chrome with a dozen tabs open is a bit of a memory hog. Safari is a lot better, but eh.
It's probably not even swapping. It's that operating systems use additional memory for I/O caching. Less memory means fewer blocks in the cache which means more slow reads from spinning rust every time you open a program or document. But replacing HDD with SSD fixes that too.
Also Chrome with a dozen tabs open is a bit of a memory hog. Safari is a lot better, but eh.