No. Having a separate GitHub is just a pain. GitHub provides adequate separation itself (you can add multiple emails and configure notifications accordingly)
Personally, I like knowing that my personal GitHub credentials stay only on my personal devices and my work credentials stay only on my work devices. I never have to worry about the two mixing and any problems that might arise.
Separating accounts is a fine principle, but for anything social (github, twitter..) some people have good reasons for doing their work from their existing personal accounts. E.g. evangelists, folks in devrel, those whose jobs include contributing to OSS or participating in open standards, and so on.
Presuming you also contribute to FOSS projects, and that you additionally use the FOSS you work on personally at work, there will come a point at which a bug you find at work will require you to fix the upstream FOSS project on your work laptop. At that point, getting the git-commit attribution correct gets annoying.
Well, if I work on it at work for work then the attribution should be under my work email. Otherwise, it should be under my personal email.
So far, the only problem I've ever had with separate accounts (including contributing to FOSS) is one time (once!) somebody selected the wrong email alias to review a CL. That took all of (literally) 10 seconds to fix.
This isn't too hard - Git supports folder path separated config settings, so usually I just have a "foss" and "work" profile.
More annoying can be commit signing, but this is actually something GPG has baked right into it - I issue and sign a new key with my work email address while I'm there, and when I quit revoke the key as superceded (and set the expiry to roughly my contract renewal period/performance eval period).
The real problem is corporate IT doesn't understand encryption or signing beyond how their vendors pitch it too them as "secure" so trying to extend any of this to actually support business processes is a losing battle.
Personally, I like knowing that my personal GitHub credentials stay only on my personal devices and my work credentials stay only on my work devices. I never have to worry about the two mixing and any problems that might arise.