The Cybertruck is function over form - everything about it is driven by the desired functionality. Specifically, it's designed to be strong, durable, efficient to manufacture, and light, which is why it's made from sheet stainless steel. The sheet metal is so strong it can't be formed, so it has to be folded, so it's got to be angular. And it's a structural skin, an approach that makes vehicles (like many airplanes) much stronger and lighter. And it's not painted, because that'd make it cost a _lot_ more - painting is the single most expensive operation in making cars. If Tesla's right, then the CT ends up stronger, more durable, lower cost, and lighter than competing trucks, and it's utility that many people buy trucks for; think of people who work in trucks for a living, like lawn car, construction, wordworking, etc. - if their truck gets the job done, is more durable, and costs less to fuel and maintain, that's all that matters. They don't need pretty formed sheet metal, paint, etc.
Keep in mind also that Tesla doesn't need to get 100% of the market to succeed - Ford has 3.7% of the vehicle market, making it the most popular vehicle made, so if the Cybertruck's focus on function over form is polarizing and they only get half the F150's market share, Tesla will be thrilled.