Are you replacing Reddit with Lenny?

Partially yes, partially no. It depends on the use case.

If I'm looking to idly scroll random content, sure, it's great!

For online community, definitely. Given the open disregard that Reddit Inc leadership has shown towards the community, developers, and volunteers who keep the show running, I don't feel comfortable contributing there anymore.

If i'm looking for specialized information on a specific topic, definitely not. Google Search + site:reddit.com still reigns here.