I am here because I got spam from you about this, at a personal email address I rarely use when signing up for things. Where did you get your email addresses and why did you think it would be OK to spam people?
Cool technology, but seems a bit of an extreme effort just to check train position. Why can't they just use markers on the tunnel walls (or under the tracks)?
They say the best camera is the one you have with you, and your phone is usually with you. In any case, some professional photographers actually prefer shooting on their phone even for planned, high-profile shoots—perhaps they like its convenience, or that its unassuming nature puts subjects at ease. Or perhaps they find it creatively freeing to be burdened down by only minimal gear.
Not for the renderer I am using (Terragen), which has specialized features for rendering skies. I do normally use GPU rendering when it is an option though.
I am working on a project right now where I am rendering atmospheric effects (lots of clouds). Even on a 12-core workstation, it takes a very long time to render a single frame to even be able to get a good idea as to what things will look like, so I'm doing a lot of changing something, waiting… changing something, waiting.
Most of the final rendering can be offloaded to a farm, but being able to quickly and interactively get a good idea of what something will look like is extremely helpful and time-saving. Right now, I'm doing some of the work on an EC2 instance with 48 cores (96 vCPU) to help with this—cost-effective for occasional use, but I can certainly see the appeal of a machine like this. And for task like compositing where you need access to a bunch of huge source files, or where maybe you have a specialized video I/O device you need to use, running in the cloud might not be practical at all.