I bought the same vac, only because it was so cheap and so far (2 days of use in) I'm impressed.
I don't use the supplied bag at all. Use the filter bag (not the foam one, that's for wet work) over the motor and just accept that you'll need to take it off and shake it out occasionally, depending on use. If you don't use that filter, then large amounts of dust exit the exhaust which pretty much negates its value.
I attached it to my track saw when cutting a cut list out of 12mm MDF and was happily surprised at how nearly full the bucket was after a dozen or so cuts.
Great value, and if it doesn't last then returns are easy.
So in answer to your question, yes you can very much use it for sawdust without the bag and empty into the bin.