Question normal

(Pardon me for posting this question I asked as part of a previous discussion. I feel it wil immensely benefit the Indian PG Residents in Internal Medicine*)
How much would publications like MKSAP17​ and MedStudy used by our US counterparts help for gaining knowledge and skills? They say that no reference textbooks like Harrison/Oxford textbook of Internal Medicine are followed by PG trainees in the US/ Canada. Instead, Mksap/ MedStudy are what they worship.
On the contrary, in India, almost all professors insist upon Harrison as the bible for our baptism. Please shed some light on this since Harrison seems like an uphill task to carry around, let alone reading from it and retaining the information!
Many thanks in advance.