Not really at all clear - the person simply stated that there was enough miles for only business class and asked if BA's business is a good experience
A response that BA's business class is better than economy is hardly much help - which economy class is better than business class?
As far as whether BA's business is any good, I would say that the best that can be said about it is that it is mediocre.
Paying $1802 in carrier surcharges plus $163 in taxes plus 150,000 miles for BA business class seems a lousy value when there are fares listed for LAX-JNB on airlines such as Swiss for $3600. Gets about $1635 saving for 150,000 miles. I would value 150,000 miles a lot higher than that
If it is a choice of using the miles on BA vs buying a ticket, I would take buying a ticket