Curated communities would likely choose to defederate from instances like that since they have no barrier for entry, and may be bots, spam, or bad actors.

If you’re joining an established instance (or work with people to create a new one), then you’ll at least get a local community, which will both give a instance content if defederated, and legitimise it so it’s less likely to be.

If it works like email, you’ll miss content that is posted when the app isn’t running. I have a cheap hetzner box going that is running my personal lemmy instance but I don’t think it would work well to have it only running part of the time.