YSK that these kinda bridges break E2EE. Your matrix homeserver will register as a whatsapp web client and forward the messages to you basically. It does work really well tho, with read receipts and media and everything.
You can always self host the bridge ofcourse, then its not an issue. There are also plans to make local bridges that are basically just a headless whatsapp and matrix client in one app that talk to each other locally on your phone or a spare one.
No speaky ze deutsch
Does this help?
danke