Yes and no. While you probably will not be too negatively affected by the lack of, say, remote control or an auto-draining system, they can definitely make your life easier. For example, remote control capabilities mean that you can control your mini AC even from across the room, saving you the time and trouble of walking over to it every time you want to adjust the temperature or turn it off.
Similarly, timers, which come built-in in many units, help cut on energy use by allowing you to choose exactly when it will turn on and when it will turn off without lifting a finger. For extra digital features, the rule of thumb is to consider how often you plan to use the unit, whether it will be your primary cooling source, and whether you have the time to manually drain it.
So if it is to be your primary cooling appliance, you may want to spend a little more to get the best features. And if you do not think you will always have time to drain the machine, then an auto-evaporation system is necessary for your own safety. It will ultimately depend on you but sometimes, it can be worth it to spend a little extra on the best small air conditioner possible to make your life a little easier.