All sorts of business and development process tracking software has existed for decades. JIRA, FogBugz, PivotalTracker, MS Project, and so on.
Trello got rid of 90% of their features, and just kept "list of lists of short text snippets". That makes it great for planning small software projects, but also shopping lists, travel plans, or sales pipelines.
Products that start with nothing more than price differentiation will eventually be pushed into a separate niche, which better serve the more price-sensitive customer base. Knowing this, it will be easier to gain clients if you can identify something you can optimize ahead of time. The smaller businesses/clients that will depend on your product will really value this and feel like they're being served well by your product, and not like they're the fodder in a price war or that they're using a bargain-basement, barebones product.
People do not feel proud that to be stuck in the bargain basement, so they're less likely to spread your product through word of mouth if you make it seem like a discount version of a well-known competitor.
As an entrepreneur, you just have to get a sustainable foothold somewhere and you can take everything else from that point. Optimizing a system for a price-sensitive audience is a good way to get started because the bigger guys are trying to leave that audience in the dust and they're usually very appreciative of the tools you're supplying.
You can just look at Google to see that it does not work all the time, Google could have replicated Watsapp, Facebook, Instagram but they failed. They even failed with Google Video and had to buy Youtube.