Hi. I'm writing here to share my experience with eatmydata in the debian-installer.
I was installing Debian 10 on a USB stick. The PC has a USB 2.0 port and the stick's writing speed is about 4.6 MiB/s. I did not measure the installation time precisely, but I'm sure it took at least 6 hours to complete with an LXQt desktop and an Apache server. I installed manually eatmydata, libeatmydata1 and eatmydata-udeb on the installer's filesystem, by extracting the contents of the archives to their right locations. I do not remember using anna-install to install the udeb, I don't know if it would make a difference. Also, I used the normal DVD-1 ISO image, without eatmydata in it. I wanted debootstrap to be called with eatmydata from the installer's menu, so I renamed debootstrap as "debootstrap1" and put along it a script called "debootstrap" which does 'eatmydata debootstrap "$@"'. I made the patch described at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=700633#50 but debootstrap complained that it cannot find eatmydata in the ISO, so I installed it by hand, no apt, I don't know if this changed the expected behavior. Also, I don't know if using eatmydata explicitly with the script and later using the scripts included with eatmydata-udeb cause some conflict and make it not work. I saw at the fourth virtual console that libeatmydata1.so was not being found by the installer in the target directory tree, it was because I forgot to make the symbolic links pointing to the real library. I made it while the installation was already running and I stopped seeing the messages come out in the syslog; I suppose it was detected later, but I don't know if it worked as it should since I did this at the middle of the installation process, not before. Anyway, perhaps I did something wrong, these are the things I remember I did not do as specified in the above message. But if everything should have worked right, then eatmydata doesn't work as I expected in my USB stick, or it is just too slow and it can not install faster. What do you say? Have a good day.

