Never heard of shock tube until today _ we used to call them gaiters -I believe in the bad old days they were made from leather for the rear shocks - some people advocate them on forks and rear shocks if dirt riding but for dry road or UK winter I would just use a quick soapy wash.
Cheaper than huggers anyway by the looks of it for the rear.
Do whatever makes you fell good - it's your bike................:-)
Enjoy the ride.
B