These seem to be “just” phone numbers. Most of which probably already leaked through the last Facebook leak. Not sure how significant the data is.
You can check whith your own cellphone, if a phone number have a Whatsapp account, without any hacker knowledge, this is not significant at all.
“ 2. Only Verified Whatsapp Numbers - Country Wise ( This is to cover all the mobile subscribers exhaustively . We generate mobile numbers based teh series allocated for the telecom operators in each countries and then verify / validate those numbers with the Whatsapp Servers )”