Most sealed boxes, but that’s not why people buy them. There’s just a huge collector market for sealed boxes in Pokemon.
If you’re talking about undervalued them decks I guess you could argue that there’s potential in the Skyridge ones but I’d rather buy oose Skyridge packs instead of decks.
That goes for any theme decks tbh, buy packs instead. Eventually we will be living in a reality where Jungle and Fossil 1st packs will sell for more than $100.
It depends on the graded card and it depends on the box.
The one thing sealed boxes/packs have over graded cards is that people are actively destroying them.
I agree with you “mostly”, BUT I picked up 1 each of all the original theme decks. They have the “signs” of possibly being shadowless. They aren’t gold stripped, but have a lot of the variations that make it possible still and I did that on purpose.
Why? Because it’s EXTREMELY EXCITING to know that my deck might be a ton more valuable. In that sense it’s still a chance of being a really awesome pull. I once bought a shadowless base set Machamp starter deck. I only knew it was shadowless because I saw a picture of the boxes insides, but not the cards directly. Wasn’t I pumped to find that it indeed was shadowless and the Machamp was still sealed! Hope my other sealed theme decks can possibly be shadowless! When will I know? I don’t know, but it’s exciting to know that someday I’ll crack’em!
I think you can shake the boxes and in the shadowless ones the damage counters aren’t secured properly, is that one of the signs?
Base is a little different because it’s base but jungle-neo destiny decks aren’t worth opening because whatever holo is inside doesn’t really hit more than $10.
I’ve been asking myself the same question for months over the Team Rocket case. Still havent come to a concrete decision so I’ve just left the cards sealed for now.
First off - incredible work obtaining that.
Second of all - (and this is just personal opinion) something that high value should definately stay sealed. In itself, the case is a great collectible even if was empty. So having that sealed would be a die hard collectable for any fan.
I know. 
I was talking about Pokemon tbh.
I’ve actually been collecting WotC-Era Theme Deck Display Cases. This collection is more-or-less a passion of mine - as opposed to an “investment”. This is especially true when you’re discussing the Jungle, Fossil, Base Set 2, Team Rocket, and Neo Discovery Theme Deck Display Cases - those have always been VERY CHEAP! However, when you’re discussing the Base Set (Both Versions), Gym Series, and Neo Series Theme Deck Display Cases - those have actually seen some growth (it’s a slow growth though). And when you’re discussing the Legendary Collection and eSeries Theme Deck Display Cases - those have seen a lot of growth (and nearly impossible to find / purchase right now too). Obviously, the Shadowless Base Set Theme Deck Display Cases are in a category of there own with the Gold-Strip Theme Decks having experienced A LOT OF GROWTH!
I would argue that those Theme Decks outside the Jungle, Fossil, Team Rocket, and Neo Discovery Sets have and will continue to see growth in the long-term. Sure, they’re not as exciting as owning a Booster Pack - as the cards within are already well documented (there’s really no surprises). However, it’s still a SEALED WotC-Era Collectable - which does add a “cool” factor! Plus, you’re guaranteed a Holo Card within each Theme Deck (granted, it’s not ever one of the “big” cards).
Personally, I started collecting WotC-Era Theme Deck Display Cases because I wanted to collect some type of case-item. Unfortunately, Booster Boxes were already out of my price-range, so I went with the next best thing (Display Cases) - and I LOVE THEM! I do think that in the long-term we’ll see new collectors switching-over from Booster Boxes to Display Cases and later-on Booster Packs to Theme Decks - some of these Booster Packs are already getting well-past a new collector’s budget, so what are they going to chase if they want something similar?