I also used bungees all the time in the TA as did nearly evryone else!
main reason because they're so quick to use(and take down in a hurry!:theyareon ),
we were advised if we didn't use bungees then keep a knife handy to cut down the poncho cords as you wouldn't have time to untie the knots if the enemy were on their way! (which is also why string was advised, as it is less expensive and less useful than Paracord)
some soldiers used to bend the hooks so they never came off the poncho.
they had other uses like straping gear on to your bag/webbing.
the bungees I used to make the poncho shelter also held it together when wrapped up in the poncho roll.
If you walk through an army training area, you'll find the odd "Bungee tree" where the soldier wasn't quite fast enough with his bungees and in haste left them!
Just as a side point The bungees i used in the TA around 1990 I still use today!
(shows how long lasting they are!)
I have gone through phases of using cord but I always find they're more fiddly having to do knots etc and then winding it back up, especially if wearing gloves.
I've recently got some of these:
http://www.rvops.co.uk/field-kit-81/essentials-20/small-cleat-1797.html
which make life even easier (watch the clip you'll see what i mean!).
I now have 4 DIY 1.5m long bungees 1 at each corner of my tarp,
with cleats so adjustable from 0 to 2m (approx).
Lazy or not, I'll be under cover before you!