What purpose do steeples serve? Are they put high up on church buildings as some sort of marketing tool so it can be seen from far away or is there some other reason(s)?
Interesting question. I managed to find an article that actually addresses this at http://www.religiousproductnews.com/articles/2007-February/Feature-Articles/The-History-of-Church-Steeples.htm
One reason: It was simply an architectural style that happens to inspire us to look heavenward.
In short, there's no doctrinal significance, or symbolic other than the pointing to the Heavens. It's simply a beautiful style that, once done, was imitated throughout the ages until it became expected.
Because steeples have bells in them
See, they know they need to pray the Angelus because the bell is ringing.
The church has always been recognised as a patron of art as it has needed to use art for teaching and inspiring . Stained glass windows often contained depiction of scriptural teachings, and allegorical interpretation lent itself particularly well to this form. Common folk found pictorial depiction easier to understand.
Thus the Samaritan would be depicted as Christ, the wounded man as man under sin's oppression.
The other way art could be used was for inspiration . Cathedrals have been called prayers in stone, depicting the heavenward soaring of men's words.
People entering a place of worship were inspired to believe they were seeing and hearing men praising God through architecture and music. God was the recipient of this worship, and men's energies were used to create forms in a way that reflected this. Conscious effort was made in the soaring interiors and ethereal singing to convey the idea that God was present in all His Majesty.
Compare this with contemporary architecture and music, where the end products have the consumer in view. Churches are patronised because they have comfortable seating, climate control and theatre acoustics, the better to hear words that comfort and beats that stir the feet to tap.