Towers are ideal for life in a zombie apocalypse on several counts:
They are elevated and stand in open areas, which makes them perfect for long distance identification, communication and sniping. Platforms easily can be built on the already existing braces that run parallel to the ground. The frame of the tower is very well suited to rigging traps for roof and siding. Towers also run in rows, opening the possibility of sister colonies.
And, if the zombie threat is overcome power line crews will ride along the lines checking the lines to assess if the towers can be brought back to normal functionality. Any survivors living in the towers will be found.
Because towers are grounded, they operate as lightning rods.
However, there are some disadvantages as well:
While elevated, and therefore giving a great vantage point, by the same token they are also exposed. If it's zombies that spot you, and if that attracts other zombies, before you know it you could have an entire horde milling about below, effectively beseiging you until you run out of food and water, or slip. If it's raiders that find you, the structure provides no shelter from bullets. Even if you construct a bullet-proof side and floor, again you could be besieged and essentially starved into submission. Less patient raiders may simply collapse the tower, or shoot you like fish in a barrel.
Furthermore, while towers are grounded, as the electricity travels to find ground, it will try to find the path of least resistance. If you are touching a metal brace and a metal wall (or water during those storms), setting up shop in one of these towers may be the last thing you do.