I think the idea of one being "easier" than the other is simply the comfort level with the medium we're using at the moment.

With metal welding, if the joint is larger or smaller as the piece is joined, it's simple to change the speed of adding filler rod etc. etc.

In glass work, I'm always stressing in getting the fibers exposed and intertwined and keeping air bubbles from the joint, etc. etc.

So you're right, one is as bad as the other and it's all in what we are more comfortable working with. Thanks to you too!