First, I don't see how playing online has anything to do with this.
Second, I think dondon's post might be a bit short, but I think it's more helpfu than the OP. The OP might be mathematically correct, but I'm sure it does not calculate an interesting value.
Look at C(5,1)=3.5. Of course it's true, playing that one Venture will give you $3 on average by Venture chaining. But the 5th Venture is not worth $3.5, because playing the 5th Venture will prevent playing (on average) 2.5 other Ventures. So the value of the 5th Venture is probably C(5,1)-C(4,1), at least in situations where you can reasonable expect to draw one Venture in hand. In a cursed deck, that might be different. Then there is also the case when you draw 2 Ventures in hand, where the formula also does not apply because the remaining Ventures has to be shared by the 2 (or more) Ventures in hand.
After all, you end up by "the Venture increases the value of the remaining Treasures by $1 (and increases shuffling of non-Treasures I guess)"