Even I, a tech-literate person, use work devices in a personal manner. Sometimes because I can't be bothered to keep them separated. Other times it's because I believe it's required. For example, I have some scripts that I execute from my synced (personal) Google drive. Why? Because I made them in my free time, and they are useful at work too.
To me I think that every company should be strictly managing work devices but I also know how much of a pain that is as well.
Depends on your industry and other security-paranoia factors. Here gmail is blocked as a potential data exfiltration risk.
In any case: key differences between gmail on a tab and an app like tiktok¹ on your phone include: your tab is far less likely to have access to your global contacts information or to other things stored on your device, isn't tracking your location and reporting it back along with your contacts list and potentially what-ever else it can read, etc.
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[1] tiktok is far from the only risk here, just by far the most prominent one ATM