To you it's worth it.Yes, I’ve had two gearbox services on the car, costing around £600, but in the 10 years of ownership I can cope with the cost as the gearbox is a delight. Worth the money to me.
To me, if I had to spend money in my late 70s on it, it wouldn't be.
You're right, I could still suffer painful problems with a regular box. Nevertheless, while theres no guarantee it's less likely and probably less expensive if it does occur, so I'll play every card in my deck and hope for the best.