Main benefits of CE are lounge access, slightly larger seat and tier points. It's a better way to travel than economy, but it's not a fantastic way to travel - don't be thinking US domestic first for example.

If you aren't a BA member, then the tier points are unnecessary. If you are oneworld emerald or sapphire, you'd have lounge access anyway. For me, key thing would be cost - how much are they asking for the upgrade.