One possible interpretation is that autistic individuals can sometimes tend to go a bit overboard when finding a new hobby. We will sometimes find a new topic so engaging that we develop a "special interest" in it and spend days/weeks delving into every possible piece of information and niche knowledge available about that topic, considering all the implications and what-ifs and following all the informational leads.
Spending merely the minimum time required (which in this example is apparently 5 days) to get proficient is harder to estimate because an autist may instead need to spend weeks learning everything. Or, they might not.