Would it have been better for the IRS to validate the direct deposits to be more accurate, or was this best to get payments to people as quickly as possible?

Some potential issue I see if you don't do some exception analysis with direct deposits:

* filed jointly in 2018/2019 and spouse is deceased * couple is divorced? join in 2018, single file in 2019? * dependents no longer dependent (deceased, filing individually, etc) * direct deposit went to wrong account (wrong account number, tax preparer's bank account, etc) * bank account closed