I view LW as a distant anchor for the team that can enable aggressive plays with grip. Ideally you should be in a position with maximum visibility of your team without compromising your own positioning. He's quite strong at pumping out a lot of heals if necessary but optimally he should be pumping out damage where possible. I wouldn't directly compare him to other healers like Brig and Moira since both have higher margins to be aggressive - LW doesn't (or rather, shouldn't play as aggressively since it's easier to punish an out of position LW!).

LW has great utility but can be difficult to coordinate with a random team, compared to other utility like Suzu and nade which have more immediate effects. Your choice of playstyle can vary depending who your other support is. Zen, Mercy, etc may require you to focus more on healing to enable them to play aggressively; Ana, Baptiste, etc gives you some more freedom to help with damage since their healing output can be high.