In general:if you hire a dev

• has portofolio
• you do not need to have his skills
• you earn money
• you must guide him
• your brain has free space
• and more

but

• you have to pay
• you depends on him or his company
• he can take your code, plugins, themes and data
• and more

 In general the people who have money manage and pay, but there are some site owners who want to make the job.