The time to zero out a file and write data is a function of sequential write performance on the drive(s) where the SQL Server data file(s) are located, when IFI is not enabled. When IFI is enabled, creating or growing a data file is so fast that the time is not of significant consequence. The time it takes to create or grow a value varies in seconds between 15K, SSD, flash, and magnetic storage when IFI is enabled. However, if you do not enable IFI, there can be drastic differences in create, grow, and restore times depending on storage.
There’s a huge performance benefit with turning IFI on.