Columbus trading away a second and getting Harris for almost 9 mil in cap space is actually an incredible deal for them based on the situation they were in. Montreal also made an incredible deal. This is a win for both teams who have very different situations
Laine 8.7M$ Harris 1.4M$ so they save 7.3M$ this years and probably a bit less next year since Harris will need a Qualifing offer, also a player like Drouin make 2.5M$ so they are saving 5-6M$top and 6M$ is usually worth a late 1st round from team that think they can make the playoff (Toronto with Marleau / Calgary with Monahan) those player were not really expected to play, the CBJ pick is a 2nd rd but they aren't a playoff team and unlike the other exemple they also aren't spending to the limit or doing it to bring someone else in...
This can't be a win for CBJ they saved money, that isn't a good hockey move since they are rebuilding they need as many asset and picks as thhey can have, having too much unused cap space is useless.
Cap space is a asset but clearly some team have internal cap, they are paying GM/Coaches payed Laine bonus, they had other deals on the table but would of had to having to retain, that wasn't a option for them.
There is no down side since MTL have the cap space this year and even more next year. It is a GREAT trade the only question is if Laine is a GREAT/GOOD player. So for MTL the trade can only look better with Laine performing, which the opposite for the CBJ the trade can't be better than it is today, but it will get worst if Laine perform better.