Small instance with about 3 users and myself online for about 2 weeks.

pictrs   930M
postgres 1.4G

I run lemmyverse.org.

There could be a few reasons.

• They want to copy over their favorite content.
• They want to try to attract more people to a community by bootstrapping content.
• They are trying to artificially inflate their instance for nefarious reasons.

Personally, I think adding some of your favorite Reddit posts is fine as long as you don’t blindly copy over everything from a subreddit. I have a couple communities that I brought over that I like, but without content, they mean nothing.