What do you think is the better investment?
I think saver and with way less headache the packs win for sure. You buy them, you hodle them and then you sell them.
You have to fight the temptation to open them yourself though.
Once the packs are sold out there are usually still enough buyers willing to pay a premium. The ask for alpha packs is 59 Steem and the bid 46. While there is not much trading going on I am 100% certain if you want to sell them fast you would not take a loss even in bigger quantities.
Beta packs appricated in price as well as they currently sitting at 21.49 Steem ask and 18.41 Steem bid price. There we even have a bid of trading going on.
You can invest in packs even if you do not play the game as the cards within and the expected value are not really your problem. It is old, it is rare so it is expensive.
Single cards on the other hand can go up in price rather quickly and you dont necessary have to wait till they out of print but you have to know which card actually are getting played and desirable.
You can get screwed if the card you want to buy gets changed. If it is an older card it can get reprinted and the market suddenly has fresh supply of a card you were buying up and thought it was scare and desirable. As I can tell this has not happened so far in Splinterlands.
With summoners on the other hand...they are always needed. With Untamed we got new ones and there are more legendary summoners in the making but so far pretty much every summoner stayed relevant.
Another canditate would be Lord Arianthus. It feels like he is in every match and there is no real alternative for him so every new player probably would like to have on at least lvl 3.
Of course this is just rambling out of my bored mind but I wished I would have not ripped open every pack I got my hands on and kept some for reselling.