You failed to factor in the possibility of your early demise or, an illness which would prohibit your smoking your stash. The loss wouldn't be yours of course. Only your heirs would be out a bit of moneys. There's no mention of something where the moneys tied up in tobacco become needed for a catastrophe of some sort, illness, natural disaster, etc. But, since you are not risk averse there is no need to consider the risk. Just spend, sorry, invest what you will and see what arises. And, there are your risks, many of them. Ignore at your peril but, you should consider them at least.
There's more. Tax free? Only as long as you aren't found out. Someone, family or friend, board member could rat you out. There is always risk. One should at least know them and acknowledge them so as to weigh risk v. reward.
And, there you are, your required due diligence all set out, tidy and neat, for you to consider. Scenarios are a fun mental activity but, don't simply consider "best possible" if you value your funds.