Broadly, I’m an evangelist, but a) spaced repetition truly is not the ideal tool for all purposes and b) it is a useful exercise to consider some of the strongest counters to your positions. Below you will find examples of things that you might be willing to read about, but would not want to actually invest time in learning via spaced repetition.
1) Facts in your field change rapidly relative to your available study time. If this is the case, you might well experience interference between the data in your outdated knowledge base and the new facts you want to replace them with. It still might be worth it to pay this interference cost to gain the value of deep memorization for the lifespan of the fact, but it becomes much less likely as the turnover rate increases, especially given high start-up costs in making the flashcards. Real-world examples: syntax for Python packages, lists of political figures, stock prices, material to cram for a near-term exam, etc.
2) You are considering learning facts that you don’t assign a high probability of truth to. That is, things that you read or hear about and just don’t believe; this is related to the fear of interference above if you are correct to disbelieve and you expect to learn the truth later. Sometimes learning these anyway can be worth it as a way to master the arguments of your ideological adversaries, but in general it is not. Real-world examples: practical advice that you consider dubious, conclusions of scientific articles whose methods you distrust, etc.
3) You are considering learning facts that you would much rather learn through a discovery process. There are things that we do in life for the sake of experience rather than learning, and all of those can fall under this umbrella, but this category also includes things that you might want to learn about in a less formal manner. For example, consider reading an engaging narrative about cultural differences in approaches to airplane safety such as the one presented in Gladwell’s Outliers. You could consistently a) not want to learn the relevant facts via spaced repetition, but b) enjoying learning the facts via his engaging narrative. In general, the limiting factors here are start-up costs and lack of fun. Real-world examples: it will differ for everybody depending upon baseline knowledge and inclinations, but things I have heard of include food, TV shows (e.g., plots, key characters), and information about places (e.g., monuments & local histories).