Twenty / Eighty is a pervasive concept. It's both about time to market and solution for the masses..
If you need to accomplish quickly some task, you'll need to focus on the core of the problem. For example, usually with the 20% of the "code" you get an 80% finished running prototype, and you'll be able to give a new service to a customer in a hurry (today, time to market is key to stay alive)
The other 80% is just useful for all the corner cases, for example to improve reliability and security and other "stuff" that's not so easily perceived by the customer. You'll need to do the homework, but you'll be less in a hurry!
Moreover, the very same ratio comes in a totally different flavour. It's about market, and having large potential customer base.
If you want to reach everyone, you'll need to take care of the always valid rule that with just the 20% of features, you are already catching the 80% potential customers. So don't run for more features than those first 20%, or they'll be outraougeously expensive and never used.
By the way, the problem still is how to find the first right 20%!