so american newbies, among others, can experience an american locomotive, essentially for free. by your logic I could question the existence of all the other Training Center stock. It is nice to have them and has another upside: unique liveries.
So the in-game tutorials for all trains since TSW3 could take place on it instead of the routes they are from, or for (loco DLCs in that case). It also enables new players, as just written above, to experience Train Sim World at no cost to see how the fundamentals work and how to drive, stop and go. Without a route it would make even less sense. It is also generally an enjoyable place and I personally drive on it quite regularily.
I rarely venture into the TC. I find the tutorials so rudimentary ( eg. nothing on safety systems ) that I prefer to learn cab controls in the route. They're re mostly intuitive anyway. And I use Raildriver which is generally not supported in the TC.
I only tolerate it as on most routes it's necessary as part of the Journey completion. Plus invariably sets those coloured track countdown markers back on which you need to switch off again in options (something else DTG seem to ignore feedback about).
Training centre is used primarily for the breaking of speed limits without the risk of being sent to the naughty corner.
