Well, if you intend to contribute to a game engine written in C++, it is of course of advantage if you can program in C++. But there are also game engines written in Go and other garbage collected languages (see e.g. https://www.dragonflydb.io/game-dev/engines/golang). There are also games written in Go. By the end of the day it's mostly a question of preference. As of Figma, as far as I understand it runs as Wasm; so essentially it can be written in any language which can compile to Wasm (which includes Go).
