A pre-apprenticeship is not a mandatory requirement to do an apprenticeship or traineeship.
You may have a clear idea of the direction you want to take after picking up skills and experience in other ways. If you are ready to test the labour market give it a go!
However, some employers, particularly in the trade industries, have a preference for people who have completed a pre-apprenticeship. They see the initiative as providing a good grounding in basic skills and workplace awareness.
In the more complex trades, such as an Electrician, many employers put a pre-apprenticeship as a must in their job advertisements, which can make job hunting a little bit tricky for those without any experience or pre-apprenticeship course under their belt.
If you can find an employer who is willing to take you on as an apprentice or trainee without the need for a pre-apprenticeship, that is great, however, by completing a pre-apprenticeship you can significantly increase your chances of finding an employer to take you on.