Litecoin has had SegWit for one month, what impact did that have?
Litecoin was not facing the same transaction volume pressure as Bitcoin (due to 4x faster confirmation times and lower relative volumes), so while the segwit lockin did raise the effective block size to 3.3~ MB, this didn't have much practical impact since the blocks weren't hitting that ceiling yet.

However, it did enable a lot of lightning network projects to start running on a realnet, and put a lot of concerns about the reliability of segwit to bed.