Yes, you need to somehow tighten up the mix and by using a software limiter hard at the end of the stereo bus it works well for that, but this is a very advanced typically genre dependent type of application, you really need to know what you are doing. Great mixes/masters are segmented and approached per segment and there are segments in a mix/master where software limiters can do an important job. In EDM with lots of virtual instruments and samples, don't do it. The same with for instance productions with lots of virtual/simulated sound (e.g. digital distortion). You simply need to know whether you can afford it or not, but it is ideal if you can afford it because it tightens up the mix in an important way and adds to the releases... Again why it is so important to create enough quality before mixing...
Software limiting the final stereo track is something only some pros can do because you simply need to understand it at such a deep level, but two stage compression using hardware is something most pros can gain from... All in all, the answer is to use hardware based compressors and limiters and focus most of that before mixing.
As a general guidance also, stay away from software effects until you craft the mix/master so well that reaching for software is mostly just because you are out of creative ideas. The important thing is to establish a good energy with your music, so that when you create music you are as passionate and energetic as possible about the creation process as well as the result, it should be pure magic from start to finish, everything else is less important and should be avoided.
In my view in order to create great mixes you need to master both the "uglify" and the "beautify" processes, simply because great mixes are great when they "rock" the listeners. There are no shortcuts, all the various engineering tools you have available have their own unique energy signature and must be used as such. It is a matter of whether you as an engineer have the audio hygiene it takes or not... Don't for instance mess around with fake digital tape saturation when it is the energy signature of real tape saturation you want.
There are things to be aware of when it comes to crafting the mix. One is that you will always be able to find a pair of better speakers or cans and hence will always improve your mixes simply by hearing it better. There are tons of similar things, like for instance that you will always find a better hardware effect than a software counterpart. The more real and true the better. No compromise, just precision, accuracy, audio hygiene and crafting it elegantly, creatively, passionately and intelligently. It's not about how it sounds, it's about how it feels.