I disagree, if someone is struggling with Master LS or any champions for that matter, the challenge of even completing them solo is actually fairly beneficial. It is an activity that doesn't take long, can load in solo, timed (master). It also teaches Guardian how to properly build for things. So for a lot of us they may be "pointless" after the new loot and the Triumphs pop but for others it is a great place to learn an approach to a challenge, with no negative consequence.