It does that in the script for you :)

Not only that, they don't do any checksum checks either, and seem to not even publish checksums.

While I understand the concern with curl | bash, this method is used in many different open source product installations. The sh file is coming from github - pretty trustful source. You can always watch it in the browser (github will not trick you into different version) but you can also curl it or just download the source from the repository (just half a page above). You can also always review and rebuild the entire tool - another beauty of the open source. But most people just want to use the tool as fast and as simple as it can be. I guess there are options for any possible taste.