Unfortunately that could be unsafe as it would use cotton thread - which has led to amputations and all sorts of a hamster chews it or gets their foot in some. The hemp mat is occasionally “shredded” a bit rather than chewed - it is supposed to be safe if chewed and I’ve never had a problem. But if chewed it would expose the cotton thread more. Same issues with all cloth and hammocks eg. The Fuzzbutts hammocks are the safest for no visible stitching and being well made but only if the hamster doesn’t chew the fleece.
For covering the top of the cage I just used to use one of the large hemp mats on top of the cage
. Worked well. The thick ones are also very good for putting under a cage to keep it sitting firm and not sliding around. Probably gives a bit of insulation in winter too.