Stationary bikes can be very effective training equipments, as long as you don't just jump on and complete the action. Whether you want to challenge yourself, improve endurance, burn body fat, increase road racing speed when you return outdoors, or just exercise and return to your desk before the lunch bell.
EZ bar curl is like that. Champions of every era have used it, and many people in the fitness world are now using it. It is the main exercise of many biceps training, if you haven’t already, you should do it.