No! The most likely reason it did not boot is that the file that dd copied to the USB drive is not a bootable file. For example, writing a CD installer to a USB drive will not set the proper flags to make it bootable.
One way to make sure that it is bootable is to check its properties through the file program. For example:
file /Downloads/ubuntu-21.10.iso
From there, you then need to look at the properties that are printed in the standard output. A bootable file should either be a disk image or an ISO hybrid file.