Trump's argument on Biden's autopen pardons is not about autopen use. It's about autopen use without knowledge or lack of knowledge.
These signed documents are pardons, not thank-you notes or greeting cards to veterans' families, WH cooks and maids. If Biden's mind were sharp as Joe Scarborough claimed, he would know these pardons would damage his legacy badly. These pardons, no doubt, are the most important and difficult orders of his presidency (Biden himself not long time ago repeatedly claimed he wouldn't pardon his son). How could Biden didn't sign them with authentic, handwritten signature, instead use a machine generated signatures? Did Biden really know these pardons? Or did Biden understand what he did?
Trump raised a good question.