My summary of BA shorthaul business class is this:-

Lounge Access (but many have it anyhow)
No one sitting next to you (but many get that anyhow in Y)
Less leg room (as many can choose exit row in Y)
Food and drink included (maybe a £10 value)
Extra Avios (usually a £5 to £10 value)
Sooner off the plane (how valuable is 3 minutes)
Priorty boarding (many have this anyhow)
An extra bag (many have that anyhow through status but how many need two regardless)
Extra TP (yes I’ve paid CE for these)
The hidden perception of priority baggage (no it’s not offered so why put on a priorty tag which only angers when it’s last off)

For a silver member I’d value CE as a £20 value over Economy (the one where you get baggage). For me that £10 is £10 on food, £5 in extra Avios, £2 in getting off sooner minus £7 for less legroom)

The TP value is personal. For some £50 extra could give huge benefits as it could make someone gold for the best part of 2 years and a futher year of silver. For others it will mean nothing.

Overall CE offers very little and for someone who is not a regular on BA and maybe has just been tempted by an offer from BA to upgrade, they will be dissapointed.

Saying that. I just splurged a whopping £38 extra to fly CE to FAO in the summer. With luck I’ll grab row one so I’m not my perceived £7 worse off for less leg room) and I’ll make sure I drink at least 3 bottles of fizz to ensure I’m on the right side. The extra 35TP could be very useful later in my TP year.