So it's 4 to 1 against AGs.
Seriously, I can see how an AG may possibly the first part of the job. But picking out the last bits of porecelain from the bog's spigot and carefully chipping away the mortar to preserve the fragile CI or glazed outer collar with a power tool isn't possible.
And he didn't actually start with a screwdriver. He would have carefully smashed the WC's spigot, before drilling out some of the mortar to ease the pressure while he chipped away with the screwdriver. The plumber who presents the vid, and the one doing the work have decades of experience between them.
So, screwdriver or grinder, which one's best?
"So, screwdriver or grinder, which one's best?" Silly question. Nobody said you would do the whole job with one tool..
I only left a collar on once I think. Then like in the video it can be simpler, a drill does most of it. But a disc still could be useful to cut radials.
As I said you can get most of it out of the way with the help of a grinder. Some would smash the pan spigot with a hammer, and blame
it if the socket broke. Others would cut into the porcelain glaze first. It all depends on the situation, what you've done and found and seen before, whether you bothered to get a better tool or not, etc etc.
When /if you get to a tight bit with the porcelain down inside the clay, you can use a small, worn disc to cut into the inside surface at an angle so a segment breaks downwards/ inwards easier. You can tap the bits towards the fresh air of your cut. Depends - I remember one which crumbled so it was easy. In the video he hasn't got any porcelain in the clay pipe itself.
You never tried a cutter? OK.
Sure you'd need whatever other tools.
Too many "plumbers" insist there's only one way because they never thought about it and never saw anyone else. And they've
only got a hammer and a blunt screwdriver. And they have written on their van that they're expert at plastering, tiling, electrics, gas, you name it. Once you've used a dozen or so "plumbers" you get to see the differences. Some are brilliant
but... Some even cut their fingers off, they're so stupid.
That's how I got to do more of my own than I ever really wanted to.