If the giveaway is setup properly, the crafter can draw the reader into their shop or blog or site, and require that the entry must state something in the shop that they would like. This means that the reader must browse your shop.
Sure, some folks will always enter and never buy. But enough folks do bookmark the shop's site and some do become customers. Others mention the site to friends who are looking for certain types of products.
It doesn't take a lot of work. The hardest part is knowing where to put the giveaway notice.
On my blog, here, every two weeks, I give away a $15 Gift Certificate to my Etsy shop. You can always find the link in my sidebar under "Giveaways...". Once you hit my post with the giveaway, you will see the MckLinky window with over 100 giveaways. Many of these are crafters, doing what I am doing.
One thing I love is that the entrants must leave a comment on your giveaway post. Those comments tell me which items those readers really want. It doesn't matter that they might not buy, or that they might not be able to afford to buy. These are the things they dream about buying. So, they are the things that I must market more aggressively. A properly setup giveaway is a wonderful way to find your most desirable products.