Pretty much agreed-- I can understand wanting new/junior employees to develop a good track record before
complete WFH. But it also seems reasonable to let a new hire that might otherwise have to relocate across the country that level of freedom and simply deal with the issue if they don't produce: not much different than how you'd deal with a new in-person employee.
I will say that, for myself, I understand my work behavior very well. If I could choose any style, it wouldn't be complete WFH. It would be 3 days WFH, 2 days in office. Just a quirk of my personality that I tend to be more focused in the office, and the time I spend there gives me a fairly regimented view of what I need to accomplish during WFH time.
Which is completely what you said: do what worked best for each employee.