I could show you, but my github account is not representative of my actual interests. That is precisely what resumes and motivation letters are for.
If recruiters start looking only at github accounts, dishonest job seekers will quickly learn to create fake github accounts, just as they present fake resumes now.
I’ve been interviewing candidates for ~5y across two companies and have yet to see a motivational letter. And most the resumes I see are either overly verbose and don’t tell me what you actually did, or are simply a soup of buzzwords.
A few of the most successful and memorable hires I was a part of have real github accounts with something more than a bunch of forks or fancy profile readme.
In my opinion, it doesn’t matter if the content isn’t representative of what you want to do at work. Seeing that you’re curious and interested in building things, trying weird experiments, and so on is a strong data point in and of it’s self.
Here’s a similar example from an unrelated field: there’s a handyman that lives down the street from me. His humble home is neatly manicured and I often see him outside in the morning, dressed for the job and working on projects. Observing the pride he takes in his craft was a signal to me that he probably does good work. And after hiring him for a small project, my hunch was correct.
Your example is excellent. I agree with you in that choosing a developer in basis to a github profile is not much different from choosing a handyman in basis to what he does in his garden on the mornings. What if there was a much cheaper and more efficient handyman living up the street, but he always works in his backyard so you have never seen him outside?
I am sure you can find valid candidates with your method, but also that you could be missing much better ones.