These things only become apparent with international travel or communication, which 99% of the world does not do on a regular basis. Even with the other comment making sense in it's points, I still disagree with it. So don't disparage that other user for having an idea with serious merit that only has some subjective drawbacks.
Timezones have existed for nearly 200 years, before international travel or distance communication was commonplace, so I implore you to explore even the assertion that those are pre-requesities for understanding why timezones might be useful.
Abolishing local solar-approximate time is an idiotic idea with multiple objective drawbacks, not to mention that it would be massively unpopular. IF you think it's a reasonable idea, you really haven't thought it through, and you absolutely do not understand how time has meaning to people, and how our entire societies are built on shared collective ideas of what different times of the day mean to us.
The level of stupidity of the idea is on par with "hurr durr, why don't we get rid of our nuclear waste by shooting it into the sun in a rocket?"