To me this is on par with Anakin built C3P0. Like what's the point?
I imagine they got a kid to come up with it like "And she should be Spock's half-sister, he just never talks about her. Oh and she has a phaser she built herself, but instead of a red laser, it shoots a yellow laser because yellow is my favorite color. It's not starfleet regulation, so she has to keep it secret, but the captain knows..."