It helps quite a bit. The relevant web APIs were retroactively rate-limitied to mitigate these risks.

https://bugs.chromium.org/p/chromium/issues/detail?id=421691

https://arxiv.org/abs/1410.7746

There were 3 research papers that came out around 2012 (almost simultaneously) that looked at using accelerometers to infer what people were typing.

Here is one of them, I don't recall the other two. https://dl.acm.org/citation.cfm?id=2162095

It could look at your eyes to infer wich key you are pressing