Actually, now it is required it seems? And it's -3days prior arrival only.
https://imigresen-online.imi.gov.my/mdac/main

All travellers are required to submit their Malaysia Digital Arrival Card (MDAC) before arriving in Malaysia, except :
Those transiting/transferring through Singapore without seeking immigration clearance; and
Malaysia Permanent Resident
Malaysia Automated Clearance System (MACS) Holder

edit: Sorry, looks like it's the same link posted above.
I just saw that's it's mandatory starting Oct' 23?
https://www.asiantrails.travel/lates...val-card-mdac/