Just to point out the obvious, but tie down straps and ratchet straps are two different animals.
True, but two different animals that are often used for the same purpose.......... 
You are correct, but. You can use a ratchet strap for anything a tie down strap will do, but you can't use a tie down strap for everything a ratchet strap will do.
One of my favorite "other" use for a tie down strap,(actually 2), is when I need to remove the front wheel or even the forks.
I have 2 eye bolts in the ceiling of my garage above my lift table.
I put the bike on the table and lift it up to a comfortable working height and hook a tie down strap to each bolt and each end of the handle bars and snug them up.
Then I lower the table a little bit until the front tire is free from the table surface.
When finished with the work I just raise the table back up and unhook the straps.
So I guess they would actually be "tie up" starps then.