There are many resources parents can use to homeschool online. Is it the best route for homeschool students to take? That just depends on the family goals and resources. In Ohio, families can get a free computer and all the books they need for homeschooling if they choose to use one of the online programs. Many parents choose this option because it is free and they think they don't have the money to homeschool. I have been homeschooling almost for free for quite a few years by buying and reselling used books, so to me, the cost of homeschooling is minimal.
Other reasons to homeschool online include 1) wanting the student to answer to someone else besides the parent for their schoolwork 2) trying to streamline the home to have less clutter and use online resources instead and 3) trying to use a different mode of learning besides just paper textbooks. These are not the only reason people choose online resources, but are some of the common reasons.
Check out my post for more information about the pros and cons of homeschooling online and the resources that are available to parents and students who choose this option - Homeschool Online