My 1st 2 multiday hammock hiking trips were with a tyvek tarp. As Kayak said, its NOISY. And its stiff, but it can be packed relatively small. My tarp was of a single piece, so no seams, etc. I used small, rounded, wooden "screw covers" in the corners to create a bulb that I could then tie a slip knot around to hold tie outs. When I saved up a few pennies I traded it for lighter weight, and much easier to handle syl.
Say what you will about tyvek, but two things cannot be denied, its waterproof and windproof. No misty splash thrus in a pouring rain, and you'd better have good stakes/roots/shrubs on a windy day.
I too carry a 2x4 foot piece on every trip for a sitting surface (no more ticks for this boy) and a "floor mat".
I also made a G4 pack of tyvek. This used a combo of tyvek tape and stitching. 8 ounces for a huge pack! But, it was not adjustable and I did not get it just exactly right. Also, one of the seams tore due to the postage stamp effect.
If costs are driving you to use tyvek versus syl then check out the article about making your own silnylon. $1 per yard ripstop from Wally's dollar bin, plus ~$4 for a tube of sil caulk, plus ~$4 for a gallon of mineral spirits and you're in business.
If you want to use cheap tyvek to find out if this is the camping style you want to follow, then do it, but you will upgrade later as time and funds allow.