Not correct. 550 foot lbs force expended for 1 second is 1 HP. Equivalent to 747.7 Watts. Both are terms of power.
You are also mixing imperial/US measurements with metric units. Usually best to stay with one system, or list both systems to help reduce confusion rather than swapping back and forth.
Most leatherworkers are not concerned with running stitchers at high speeds, rather they are concerned with starting torque at low speeds, and being able to continue the stitch line at low speeds. Obviously a more powerful motor will be able to provide greater starting torque and that is what is required for stitching thick and/or hard temper leathers. After several trials, many users will go with both a good servo motor, and a speed reduction pulley set to handle these situations.
I see this is your first post here. Welcome to the forum. Lots of information and help is available here, and of course all members new or old contribute to that.