Rack servers may seem like a more costly solution to network storage, but in reality they can actually save a great deal of money for companies in the long run. For those who need very little in terms of storage, there may well be little to no need for such a solution, but for any company that needs numerous servers, they are likely to be the best option all round.
On the surface, it may seem that tower servers take up less space, cost less and will leave more space for cooling, but the whole design of rack servers makes the latter far more efficient in almost every way. Rather than cooling the servers individually, the racks have an aisle through which cold air will pass, ensuring that all servers are kept cool from one source, potentially saving money and generally making it easier to keep every machine at the right temperature. The way they are arranged means that far more cold air can get to the machines far quicker.
In terms of space, using racks will allow far more efficient use of space than trying to get the same power from tower servers. By saving a huge amount of space, you are also saving money by being able to get many more servers into a smaller area and therefore you are able to either save on rent or even simply be able to use the saved space for other things.
As network storage goes, using rack mounted servers also simply makes things far easier. By arranging servers in racks, you can easily slide an individual machine out should a certain server need attention and then return it to its original position without unplugging any cables or affecting any other servers in the process.
For ease, efficiency and potential, rack mounted servers will win every time, making them well worth any extra money they might cost above and beyond a more simple solution.