In praise of Alum

I like how it feels, simple as that.

Yup. It extends the whole rewarding ritual of shaving.
And — it prepares you for the sting of the aftershave splash.

I totally agree. Plus, it gives good feedback on your shave.

Never have used antipersperants, which are absolutely loaded with potassium alum. But I do keep an alum stick to close off wheepers when wet shaving. Works like magic. Bleeding stops instantly. I don't use the alum stick for feedback as I'm wary of its side effects. The alum doesn't come into contact with me unless I'm bleeding freely. Otherwise it sits on the window sill. The tube could last several lifetimes. It's a natural product, sure, but so is lava from a volcano. I wouldn't apply lava to my underarms. And I wouldn't apply potassium alum to my underarms.

Never have used antipersperants, which are absolutely loaded with potassium alum. ...

Are you possibly conflating "potassium alum" with "aluminium chlorohydrate"?