Until quite recently, accurate clocks were either nonexistent or very expensive. In fact, standard time wasn’t invented until the nineteenth century, so even when clocks became common, each person set his clock by the sun, which meant that they could differ considerably. The time of day was very approximate—for example, in the New Testament, everything happened at either the third, sixth, or ninth hour. People told time by the position of the sun, which is part guesswork, and on overcast days they had to go by feel.
So you can see that until very recently, it was impossible to fix Sunday morning worship at, say, 9:30 and expect everyone to show up on time.
In the beginning, Christian worship was at sunrise. Sunrise and sunset are the only two times of day about which everyone can be unanimous without accurate timepieces. But after Christianity became legal, pious Christians wanted to worship at different times of the day and on all days of the week, so it became necessary to develop some means of announcing the time of worship to the public. Church buildings acquired bell towers for this purpose, and they evolved into today’s steeples. Now that we have accurate and inexpensive watches, we don’t need church bells to tell us when to set out for church. So steeples have become decorative—though I understand that their original function is beginning to return.
Synagogues do not have steeples for the simple reason that ringing a bell on the Sabbath violates the Law.
Steeples are more or less a western European innovation. Churches in Bavaria, Austria, and points east have historically had domes, not steeples. Steeples have never been a feature of churches in Africa or Asia, either.