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.
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.
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into it - I issue and sign a new key with my work email address while I'm there, and when I quit revoke the key as superceded (and set the expiry to roughly my contract renewal period/performance eval period).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.
(I mean any dangers at the account/permissions/privacy level - separate from "having two separate accounts might be better for work/life balance" sorts of concerns.)