I used to do cosplay. Many costumes from movies, TV-series and anime are of characters that wield guns, often unique or at least quite distinctive guns. Carrying the correct gun is sometimes a thing that identifies the character, and therefore is an integral part of the cosplay.

For example, I used to cosplay for charity in the Star Wars costuming club 501'st Legion [0], where for most costumes a blaster gun of high likeness to the original is required. It has hundreds of members in California.

These days, it is very common to make cosplay accessories through 3D-printing. A ban on replica guns parts would hit the hobby hard.

[0]: https://501st.com/