@rich o brien said:

I have them as shortcut keys. If I want to TRIM I just copy the cutter to memory buffer before the boolean. CTRL+V will bring it back.

That's the key point.. I'm a "toolbar man" can't remember that many button, I have really bad memory. 😢
But I have custom toolbars set up, so I can keep a compact group of just 3 buttons: add, group-add and split (from BoolTools2).
I always feel that split is the most versatile "subtractive" boolean.
Your point about trim is valid, but what if you need intersect?
Split may serve as subtract, intersect and trim and takes a single button on my toolbars.

But.. probably the real reason why I prefer Split is that, for the kind of models I mainly do for work, I barely use booleans. They tend to create unsuitable topology..
I use booleans mostly when I do hobby projects to build something out of wood.
I don't want to waste wood, so with Split I can more easily keep track of the leftovers and scraps to do this kind of stuff. 🤣

Scraps.JPG