It's been a Blues staple for a long time. They'll get a small lead and just bleed the game away with their physicality and elite goaltending. More times than not it has worked. Usually versus finesse style teams like Chicago or Dallas (in the past, but this year Dallas pretty much tried the Blues blueprint). It is almost impossible to sustain it long enough to win 16 playoff games though. Eventually you'll meet a team every bit as physical as you and too talented on the offensive side to just sit on leads. The Predators Cup run crashing down versus Pittsburgh is another good example of such. Though Pittsburgh wasn't really a mirror to the Predators, they were just so good at scoring you couldn't keep them off the sheet no matter what you did. Much like the 3x Chicago cup winning teams.Yeah, that looked terrible last night. Like they got up 2-0 and stopped playing. No offence, no forecheck, no puck possession. Very concerning. SC playoffs can turn on a dime, but the Blues better figure it out quickly or they're toast.
That's exactly what Boston brings to the table. You might be able to sit on a 2-0 lead versus a Dallas or San Jose. You cannot versus Boston. They will find those same gritty goals you do and I think they're better at scoring than St Louis is. They also have a better powerplay and as good as Binnington has been Rask's stats have actually been better these playoffs.
The Bruins are essentially a direct mirror to the Blues. Rask to Binnington. Chara to Parayko. Explosive skilled offensive players on both sides. Boston is just a better version of St Louis is my thought. Doesn't mean the Bruins can't be upset, but it would be that, an upset.