I bought silver chests til I hit the 200,000 milestone and after that, meh. The tier rewards aren't worth the time needed (I couldn't care less about the gold, but hitting the X10 silver chests enough times I can't be bothered with) and the tier rewards are also pointless, an ugly skin and some chests that will invariably include 3 stones for a hero i have maxed and some scraps I have 2000 of.
Can't wait for this weekends contest. Use 2 heroes in FP and Coli not everyone has for a tiny amount of points and gain the large amount of points needed by, tada - spending diamonds of course.
And Disciple Beowulf will win it again on S5, as is the law!