I am using a circular knitting needle and it helps me keep my needles together. It also prevents me from having to create a seam, which is so difficult to me. I like using a knitting machine as well. Sometimes it is a lot of work to keep the yarn on the needles. It takes a while to learn how to use the knitting machine, but it knits faster. It takes a long time to complete a sweater by hand. It may take about twenty hours for me. On my machine it takes about 10 hours, but I don’t like the way I put the seam together. So, sometimes a circular knitting needle is needed. You can get a circular knitting needle for 60% off here.
If I was starting out knitting I would use a circular knitting needle to keep up with the needles.
I would want to learn how to use straight needles after using the circular needle. Projects without a round portion wouldn’t need a circular knitting needle.
Once I understood the knitting process, I would move on to a knitting machine. I believe troubleshooting is easier if you understand what is going on. A knitting machine also helps keep your project even and the same gauge.