this is not a question about markets or how to mine, but rather about the lifecycle of a coin on the platform. WHY would anyone purchase coins on an ICO? Is the aim to pick an ICO that might just hit the jackpot? Seems like a bit of gambling, and seems like a way for a startup to get capital without actually giving away any shares.

Now, what does one do with the coins? Unless they want to use the software platform which is built on this coin, in which they can just spend the coin to use the service (e.g. Veredictum).

I understanding the mining, you provide computational power and get paid for it, a block you mine gets used by someone on the platform and they pay you for it. Or you hang onto it until the price goes up, because so many people are using the platform that the price fluctuation happens due to supply and demand.