If you use a lot of power during a price spike, you can expect to get a much higher bill than normal. Some people are OK with this, but most people will want to shift their usage away from price spike periods if possible.
You see, for most people, wholesale prices are cheaper in total over the year, but they’re not necessarily cheaper in every month of the year. Over the last twelve months Amber customers with average usage saw bills $30-50 cheaper than a traditional plan in most months of the year, but then $80-100 more expensive in Australia’s hottest month, January. Your January bill could be more expensive than this if you don't pay attention to price spikes.