Yes hot glue does hold fabric together pretty good.
The fabric is porous and hot glue works good and best on porous surfaces such as clothing and fabric to bond them together.
When you apply the hot glue to the fabric use something such as a roller or plastic knife etc to press down on the fabric while the hot glue is still hot.
Pressing down on the hot glue and fabric presses the hot glue into the fabric which helps the hot glue bond the fabric together.
I've used hot glue on fabric a lot and it's always held the fabric together.
Just hold the fabric together and press down on it for a few seconds while the hot glue is cooling down and the fabric should hold together just fine.