Absolutely, we don't have a lot of info here for sure. Once again we are left to assume and yet offer advice. Thus, Tommy, I know it will, but again, if there is something even slightly safety about this, my info was strictly, MY ADVICE for the welding of the other rebars. Even then it is not always accurate. And even before I got heavy into welding, my dad had 9018 laying around at the farm in OR back in the 60's. The odds, pretty slim. But you don't know, he might have some.
I did not go 'overboard' recommending strictly from the code. But, I felt it critical to at least offer sound advice. Shoot, you can weld it with 6010 or 6011 too but most of us wouldn't.
Anyway, and I agree that for many uses around home 7018 is 'adequate'. That may not make it the best depending upon the rebar.
I have seen too many things made from rebar because it is so cheap compared to round bar and other steels that it is scary. Especially when you look at the usage of the product, the electrodes used to do it, and the quality (more properly the lack thereof) of the finished product.
Have a Great Day, Brent