The purpose is for socio-economic upkeep.a
Baby Boomers are called Baby Boomers because when the torch was passed to them, they didn't know what to do, so they had kids.
When Generation X got passed the torch, they didn't know what to do, so they created Consultation careers.
When Millennials got passed the torch, erm, we kinda fumbled it a bit. But that's when Internet Business became a thing. The trouble is that each generation is larger than the last, and with Millennials, it's sort of divided. Half of us are old enough to remember what life was like before the internet and what needs to get done, and the other half of us that was before their time, and so they struggle with trying to correlate direction now that context seems to be lost.
And Gen Z sees our fumble, gets terrified that it might happen to them too, and defaults on traditionalism by going to college, but also like later Millennials seem to not be able to find a clear punchline or contextual meaning to anything, because of how scattered unregulated media content has become (as opposed to television and film BEFORE the time of the internet).
People divide age groups into labels for socioeconomic timeline purposes. That's all that it is. It's business and economics lingo.