The short answer is 'yes'. This is a black and white answer and in the real world, answers are more nuianced. As I ironically say sometimes "the gray area is where the fun is". A UPS is a device that does several things for your power hungry equipment.
Firstly it provides power when the hydro mains are down. In the modern world this does not happen very often. A few weeks ago in Thunder Bay we had an ice storm and power in the Intercity area was down for several hours. At TELECO we have a UPS that serves our network, server and phone infrastructure. This does not provide backup power to the staff computers but a few years ago we decided to upgrade all PCs with latops. Why? Laptops have built-in batteries. We were still able to answer calls and assist our customers during the outage. If you do not use laptops (or need more time than the battery will last) then I would recommend that you purchase UPSs for critical staff that need to have their computer running during an extended power outage. If it is critical that your server, network and phone infrastructure be up and running then just a UPS is not enough. You should look at developing a plan that encompasses UPSs, generators, infrastructure redundancy, offsite contingencies and the list goes on. We can help you to navigate around this and related issues. We will help determine your comfort level when it comes to risk versus cost.
Secondly a UPS stabilizes line voltage. This keeps power around 120V. Low or high voltage fluctuations can cause issues or damage sensitive equipment.
Thirdly a UPS conditions the power from hydro. Most importantly this protects your equipment from surges and spikes which can also serverely damage electronic circuits. It can also help protect from EMI. You can certainly purchase less expensive surge bars that will protect your equipment, but it will not help with the first two in this list.
When purchasing a UPS consider the maximum equipment load and runtime of equipment on the UPS. UPSs designed for server racks will have the option to add extra battery modules to extend the runtime when the power is out. How long do you want the equipment to run during a power outage? I would recommend that you talk to an expert who knows how to calculate wattage and runtime to determine the best solution for your situation. For larger UPSs you may need to install electrical circuits that are required for the amperage of the UPS. Our sales team would be happy to consult with you to help choosing a UPS that fits your needs. Call them at 807-346-7264 or email at firstname.lastname@example.org