In the classes I teach to inexperienced individuals, the students are told that the performance evaluation is the most important part of the class. If you don't pass that part you don't pass the class. The written test and presentations are important however, any of the concepts or questions can be clarified verbally if not fully grasped by the student. Not everyone has the necessary hand to eye coordination to be a safe operator after the first or second day of practice.
An online class might have a limited value as a starting place for a forklift safety program to meet compliance requirements.
The hands on portion is where the learning happens.