critique:  Bitcoin is purely digital & backed by nothing, and therefore has no intrinsic value.

rebuttal:  "Intrinsic" value is a faulty concept. It's always the case that humans value something based on its usefulness for a specific purpose. The value is not an inherent property of something but a reflection of people's demand for it. Similarly, something only needs to be "backed" by something else if it is missing the properties that people value.

Bitcoin has many attributes that are fundamentally similar to gold (which humanity values at over $10 trillion), and are often superior precisely because of bitcoin's digital nature.

People have historically valued gold above its industrial use (electronics, etc.) because it has properties that made it useful for reducing the friction of exchange, such as scarcity, fungibility, durability, etc. These properties generally define something that can be a good money and store of value.

Bitcoin has these same properties, often taken to an extreme vs gold due its digital nature, plus other capabilities that are not possible for a physical object. This is why bitcoin is often called "digital gold".