There are various ways to set a task for a lesson in a classroom. You can do it verbally, which means that most people will forget what they need to do by the time you have stopped talking! You can do it on the whiteboard, but this could mean wiping off valuable notes that others need. You could do it through Powerpoint (or similar) but this does mean that the amount of information you can display is limited. You could always give out a printed handout with the task on, this does mean using paper and restricts you to mostly black and white and if you have the budget colour; of course no media such as video or sound.
Using the VLE to “host” the task allows the learner to have access to the task itself as well as any resources (such as video, images, text or audio) needed to complete the activity.
You can also use the VLE itself to be used to submit the responses or answers to the activity. You could use the assignment module or even a discussion forum.
It wouldn’t be necessary for some activities for all learners to have access to a computer, one laptop per group for example. Though if it is an individual task then one computer per learner may make sense. The task could also be completed by remote learners or those on placement or in the workplace.
Learners can then always at a later date refer back to the task if they need to, for example to help them complete an assignment or for revision purposes.
Of course also by placing the task on the VLE it makes it much easier to use the same task the following year or making a copy for another group.