They're probably not going to be the best investment, no. Unlike when they were dropped in Classic, people are keeping them because of their value on RS3 thinking they'll be just as profitable.
If they never gave them out again, then *maybe* in 3-5 years (if 07 is even around then) they could be worth something. However, I have a hunch Jagex fully intends to have these items not be the cash hordes that they are in RS3 - meaning they probably won't give second thought to dropping them every so often/on holidays.
A better investment idea might be resources that are commonly botted, such as ores. If the number of usable bots goes down, or the rate of banning keeps going up, then these items will increase in value as the supply goes down.
...just a thought