Yes and No. There are thousands of Lightroom Presets on the market, all with varying levels of quality. Whether or not Lightroom Presets are worth it depends on the following factors:

1. The User’s Level of Experience in Lightroom – Lightroom Presets are essentially shortcuts to a specific predefined look. If you as the user have the knowledge and ability to get to that specific look without purchasing the presets, then you could simply create your own presets. However, a well-developed, well-tested, and frequently updated set of presets should give you more consistency from image to image than your own presets. Unless, of course, you also thoroughly test and update your DIY presets.
2. The User’s Need to Save Time – For busy professionals, presets are a critical photo editing tool, as they allow the photographer to save valuable time in photo editing. For amateurs who aren’t necessarily counting their time in photo editing, however, the need to save that time may not be as important. In fact, some photographers might actually enjoy tweaking each photo and prefer starting from scratch each time.
3. The Creator’s Experience and Legitimacy – Presets can be a profitable product for photographers and “influencers” to create, creating an incentive for some to jump into it without the proper experience or skillset. The easiest way to filter out these presets is to simply research the person or company who creates the presets. How long have they been in business? If they’ve been making presets for multiple years without any public complaints, then the presets should be decent. How many preset packs have they created? If they’ve created multiple preset packs, then their latest iteration should be more refined than previous versions. How often are these presets updated? If they rarely update their presets, then they may not be making critical adjustments or listening to their community.
4. The Size of the Preset Community – Creators will often update their Lightroom Presets based on feedback from the community. Simply put, the more people there are using the presets, the more refined they should be. More people using and testing the presets creates more data and more feedback to help push the product forward.