I tend to just use the AVIOS estore - probably need to shop around more for when TCB is better or whatever but keeping my life simple etc...

But if posters above are correct on the maths that with the bonus AVIOS are 0.8p each then that £300 in cashback will get you instead when converted (based on my redemptions varying between 1p with BA and 1.4p with AA domestic in the US) between £375 and £525 of flying and for some might be a top up that enables them to use a 241 or something which would increase that further.

So for people with a definite use for it/always find it easy to use their AVIOS it could be worth a lot more than just taking the cash. It's all about what you'll use as it always is in the points game. Stacking them up for the sake of it is ofc much worse than just saving real cash which you can use for anything - but if you have a use in mind where 300 quid buys you over 500 and you were definitely going to travel anyway it's effectively better than cash ofc.