You lose the card draw, but you protect all permanents you control with counters, including planeswalkers, and you tack on a free proliferate
That's especially true for the 3 strongest ones
Slagstorm is one of the best of the cheaper mass removal effects as it comes out fast enough to stop an elf or affinity deck getting to an unbeatable position yet still hits the vast majority of things you can cast for the same cost or less
The key though is to assess which cards cross this threshold, as merely good rares arent worth twisting your mana base for
Well, there are cards that change this dynamic, either giving you a huge benefit when you discard your own cards or by punishing people for having few or zero cards in hand
The increased drop rate of foils from 1:67 to 1:45 and the release of Set and Collector Boosters have dropped the average price of new common and uncommon foils significantly