I use a specific mail adress just for deltachat, but I think about users who don’t make that.
I get read receipts (a lot of them) in the main mailbox (received mails) of my mail client (whatever the mail client).
Why Deltachat don’t put them in a specific folder?
deltachat can only move received email into the Deltachat map folder when it is active, If you want a better experience, then you either need a deltachat that is running all the time, or even better a server side filter rule that your email provider already sorts the chat-email into the deltachat folder automatically.