Even with a good SSD and processor, LibreOffice takes a lot of time for the first fire. Then, as long as it's in the memory, you can fire it relatively instantly but, it's not "3 seconds flat".
Kinda reminds me, back in the day Microsoft would add a startup service that would preload Internet Explorer and Word (I think those two) into memory, because they started so slowly by default. Trying to get a leg up on the competition, I suppose, since obviously Firefox or what have you wasn't pulling similar tricks. I'd disable stuff like that in msconfig to get a faster boot time, but was always shocked by how slow Word would load after that.