A standing mixer is a great tool for baking/making dough, I use it also for beating white eggs or heavy whipping cream. Note that I use it when I have a large quantity to prepare or when I am short in time and want to do other things simultaneously.
I prefer to do things by hand (cutting with a mandoline and kneading dough by hand), but when time or quantity are a big issue, I use these tools.
The need for them is entirely based on your schedule or cooking habits, I survived many years without them.
"Tell me what you eat, and I will tell you what you are" Anthelme Brillat-Savarin