The benefit is that once big tobacco has bought into ecigs (which was inevitable), it becomes extremely unlikely that ecigs will be subject to an outright ban. However we already have that situation in any case.
The negatives are that a big tobacco version of the ecig market is useless for most community members. This is because BT's ecigs can survive under the toughest regulatory climate, but what does it for us is the full and unrestricted range of all possible options. Indeed BT will welcome strict regulation because it will remove competitors.
Their products will comprise minis, with tobacco or menthol flavors only, prefilled cartos only, no refill liquids, sold only on main street. That's all they are interested in.
What we want to see are all the options, which will be at risk: a full range of hardware including 2nd-gen and 3rd-gen devices, all flavors, all head options, all liquid options, with both main street and web sales.
BT's lobbying/pressure money may be useful but they have no reason whatsoever to protect what we see as the raison d'etre of the system: its very wide range of options. In fact they gain if all that disappears.
So what we are left with is protection of the basic system availability (which we already have in the USA), along with not only no protection of what we see as the real value of the system but also a strong motivation to allow that aspect to be regulated away.
It's true that BT will eventually need expansion options when the market is fully saturated with minis, but they can address that problem later on when it needs solving. First they need to fix their marketing, packaging and distribution issues with a whole new product. Phase 1 of their ecig market penetration will last for 10 to 15 years, so it would be to their benefit to see all competitors removed for that time. At around 10 years down the road they can then exert pressure to have the permitted product range expanded gradually, to allow them to expand.
They have no need or desire to see any other than 1st-gen ultra-restricted products around for at least 10 years. At that time they can apply pressure to allow the mid-size models, or whatever other upgrade will be to their benefit. Once they have their main street distribution sorted out, they will be happy to dispense with web sales, and Blucigs (for example) won't suffer at that time as main street will take up the slack caused by a ban on web sales.