For some people it definitely isn’t a ‘slam dunk’ decision, and it does indeed depend on one’s personal circumstances and preferences or aspirations.
I joined BA after a career change, and in full knowledge I would never make it to the top payscale - but I wanted flexibility and options.
In that regard BA offers more than most (at least in the U.K. ). I didn’t want to have to keep moving companies just because I wanted to change fleets or perhaps explore different part time options.
There are definitely cons to joining BA after 30-ish but to be honest, variety and quality of life were more important to me. And as mentioned above, the LHR night curfew means one can work something approaching regular working hours on shorthaul.
Appreciate that for some, it’s not necessarily a step in the right (or even desired!) direction.