To add a voice for the other side of it - I've found those quite useful. I follow people all over the world and live in London. When I have a look at twitter in the morning I actually like that it'll show me (some) tweets from people I follow in the US or Asia that I would've easily missed. I can't say for sure but it seems to prioritise them in some way based on my previous interactions or how many times the tweet in question was interacted with overnight.