Yeah, the early LTE networks were not much faster than the mature HSDPA+ networks from the end user point of view. But it was certainly a necessary evolution to give the networks enough capacity to handle the ever-increasing data demands of users, 3G would not have held up for much longer.
It was sufficient to do most things, even streaming online radio. The biggest downsides were that latency was high and the annoying speaker buzz problem. 3G was a big step up. I never felt like LTE came as much of an upgrade over 3G, from there user point of view, so I question it being the defining technology for smartphones.