I am making a baby blanket for upcoming baby shower. Should I also buy something from the registry?

I refused to have a registry for my baby shower. It may prevent receiving more or less items than desired and make sure you get what you like but cuts out creativity and can make people feel forced. I don't like being told what to buy. Ever.
After accounting for the cost of your time and materials I feel strongly that it is entirely your choice if you can afford and want to spend more on the shower. Whether a box of diapers, cute outfit you find on your own, something from registry, something else you made or nothing. I assume there will be many other opportunities to buy things for your future niece or nephew. A baby shower isn't like a wedding in the sense that you need to "pay for your plate" most are just grateful to feel the love and support!