Great question. The Mini is the perfect iPad, but only if it fits your use case. SO here's where it fits in with my digital life. I own the following - a 15" M2 MacBook Pro, iPad mini & iPhone 12 mini. My iPhone choice is a function of device weight & the pockets in my trousers. Small rules. It's a very functional device.
Compared to the iPhone 12 mini the iPad mini offers a significant step up when it comes to screen size particularly for media consumption, it's good if not great for reading, perfect for email on the go, light photo editing duties, inflight entertainment. A perfect digital travel companion. At home I use it mainly for Netflix, YT, Prime, ATV when in bed. If your primary focus is 'doing' stuff, its small size might be a compromise too far.
For everything else the 15" M2 laptop reigns supreme.
However, if you happen to have one of the larger iPhones the value proposition of the iPad mini is undermined. Whether you'd benefit from owning one is a question only you can answer.