-1.
They add balance so it isn't the same thing every single round. It keeps the game mode from being stale and gives people an intermission.
Of course, it interrupts the flow, that is the point.
They 100% add value to JB.
And while you knock giving CTs a win every now and again, it is important.
The bane of jailbreak rounds is when no round is actually played. It encourages rounds to be less than 1 minute,
It's part of the whole reason I play JB.