Still used all the time, Baz.
Also alternatives..... zinc; fibreglass; aluminium; EPDM (rubber); torched built-up felt etc etc
Lead is still preferable for bay windows. Its substantial weight means that it just lies there. If it's fixed properly, it takes a very strong wind to shift it.
Also, it looks good in a traditional way. It's definitely very long-lasting as well.
I'm talking about pitched roofs here. For "flat" roofs, any of the alternatives would look as good.
Lead can oxidise easily. It's vital to finish it with a rubbed-in coat of "patination oil" to stop this. Untreated lead eventually can look awful. Blotchy with patches of oxide.