Scotchguarding

Yes, I would.

I decided not to have our new cream suite Scotchguarded because I was rather worried about the chemicals - one large glass of red wine later I wish I had!

Yes, I agree with Annsixty.
These welcome cups of tea in bed, do get slopped about! My DH brings me one every morning, and resists the idea of using a small tray. Why?

For the sake of £70 get it done.
When my family were young shoes were not wiped properly and they would run straight upstairs .
When my H was older he would bring me a cup of tea and slop it on every stair.
He had dementia so telling him not to was useless.

Scotchgaurd is excellent in the case of spillages and dirt, but how likely are you to have spillages on the stairs? Presumably your hall will have a doormat so any outside dirt wouldn't find its way in?