Of course a serious baker needs both, but when you’re starting, a small electric hand whisk is just fine. That’s all I had for years and only when I had the space to leave a stand mixer out on the counter did I actually buy one.
Now I have a preference for my handwhisk when making cakes by the creaming method e.g. Victoria sponge where the fat and sugar need to be perfectly mixed in, but when I’m making something that needs a lot of air beating in but no real mixing of fat and sugar e.g. meringues, genoise, then I go for the stand mixer as it saves time. You can of course use a stand mixer to make a Victoria sponge, but I find it a faff having to stop and scrape down the mixture all the time, and I don’t think the result is as good.
So I’ve been teaching my baking student to whisk ‘by hand’ using the electric hand whisk alone, as I think it helps to get a feel for how the mixture changes and you can actually see the changes as they occur. The cakes are turning out not too bad. This is the Ginger cake that was the student’s first attempt at cake making ever. Pretty good huh?