This Tweet explains why Stealth invoices was added.

You can now enable "Stealth Invoices" on your robot profile 🥷

Enable it for invoices with succinct descriptions. Ideal if you are using a third party lightning wallet (i.e., not your own node).

Stay private 🤖🤘

https://twitter.com/RoboSats/status/1558579785361670148 https://nitter.it/RoboSats/status/1558579785361670148

And here's the issue in the RoboSats github explaining further:

Add 'stealth invoices': an On/Off toggle for lightning invoice description #168 https://github.com/Reckless-Satoshi/robosats/issues/168