yes but the time it takes to create a new plot, get ideas, find how to implement them, take time to code it, so that you don't have a taste of how sessions work and retire 2 months later?
Why?
being support requires problem solving
it requires patience
good temper
and amicablity
advantages of mock sessions:
+ gives a first glance at being support (patience and temper)
+ fast to do (saves everyone's time)
+ gets you problem solving skills
+ displays amicability
- hard to manage...