We decided not worth the hassle. we had a tough lockdown experience. My dd aced her SATS despite going to an awful primary school. She is now great at maths and thriving at a strong comprehensive (we are lucky to have one) and predicted all 9s at GCSE except English.
What they are capable of at 11 doesn’t really tell you how life will unfold. If the preparation for the test is building a gritty determinism, resilience, a realisation that hard work is worthwhile, and most of all a love of learning, then what’s not to like?
If it’s not achieving those things then - well, yes I’d ask is it worth it? You could save time, energy and cash for extra cultural or museum visits, books, a pet to care for, new pastime/sport/hobby, music lessons, online enrichment of the curriculum, or teaching the kids how to grow plants or saw wood or go camping or culture yoghurt or plan a holiday etc.
There millions of ways to grow a child.
So have a go with the test, final push, then live.