It is pretty vile to make smart arse comments about what people should do after the fact, when they cannot do that thing now!
How wonderful that you'd do anything at all (really, anything, I'd bet you actually wouldn't) to have that spare £100.
Now what would you do if you had your perfectly saved emergency £100, and you had an emergency, spent it all...
And then the next day, or the day after, you had another emergency?
This happened to me - one week our boiler died. We had some spare, we got it fixed. Then the washer died.
My spare fund was gone - what do I do, go on a magical quest for a money tree?
It is nice to have an emergency fund, I always aim to have one these days but it's taken me a bloody long time to build up a couple of grand and a clear credit card, well over 10 years. I expect to see my entire emergency fund wiped out by the COL.
Then I'll be back where I was a decade ago, hand to mouth and nothing in hand for disasters. Joy. But clearly, that'll be me being foolish eh.