Worthless might be an exaggeration. Sorry I don't check in to reply very often.
Sure they are good enough to shoot a squirrel but if you're shooting targets and trying to go sub MOA, you need adjustable parallax. I took my Remington 700 with a scope with fixed parallax to a 25 yd range to sight it in and couldn't get groups smaller than 1/2" and I considered that "horrible". With my accurized 10-22 with parallax adjustment I hardly ever shot two shots whose holes don't touch at the same range.
For shooting varmints or even deer, you can live with that error and that is why hunting scopes have always had fixed parallax. But for pushing the limits of the gun, you don't want your cheek weld to be the most important variable.
PS the results mentioned above with the 10-22 are with the Simmons pro Target that I recommended above. Still $100 on ebay.