As I've been using titanium for many years I'll just throw my 2 cents in...
While I have Ti watches by Seiko and Panerai which scratch to hell so easily... I also use Ti in most of my bike parts - frame, fork, bars, seat post, cages, skewer, cassette...
And they all scratch extremely easily... But they are also very easily polished. But they are big parts, without glass or plastic you have to worry about scratching...
While Ti is lighter, it is more brittle. If you take a rod of steel and a rod of Ti, you could bend the steel rod (think strong man style) but the titanium rod would finally crack and break in half.
This is why you cannot use titanium for weightlifting bars etc. With everyone saying 'it's stronger' you would think they'd use it for where you need the strongest metal of all. But no - because it's brittle.
But it can be used in human bodies because our body parts aren't subject to that kind of bending - and the lightness and strength is closer matched to human bones than steel.
TLDR - It's great for applications where it will not be hit by extreme bending pressure or it will crack and break, and is lighter than steel and in some ways stronger than steel - yet it's more scratch prone than steel.