Sekai Saikou no Ansatsusha, Isekai Kizoku ni Tensei Suru

[David75]

He had one stone explode, but because he far exceeded its capacity.
He's smart enough to know the limits of the stone and OP enough to create far better ones with a much higher limit too.
What he lacks now is a magic bag to always have them ready.

My guess is that those stone will help his assistants. He chooses people with mana, but they will never have levels high enough for his plans, so those stones complement that.
I guess having some stones can help using some power without activating your mana, better stealth attacks

[Kraco]

He had one stone explode, but because he far exceeded its capacity.
He's smart enough to know the limits of the stone and OP enough to create far better ones with a much higher limit too.
What he lacks now is a magic bag to always have them ready.

My guess is that those stone will help his assistants. He chooses people with mana, but they will never have levels high enough for his plans, so those stones complement that.
I guess having some stones can help using some power without activating your mana, better stealth attacks

I'm fairly sure that when dynamite was first developed, most didn't expect that if it's left to sit for some years, it would start to "sweat" or "weep" and become dangerous and unstable. It doesn't really have anything to do with how smart he is or not, apart from the lack of caution. When you have a huge pile of those magic pearls in a bag, isn't it possible they will slowly leak mana? Where does that mana go? From the outer stones, it might just disperse into the atmosphere, but what about in the very middle of the pile? The leaking mana would actually concentrate there, as we can assume mana isn't even affected by gravity to a significant effect. The stones in the middle of the pile might then, instead of leaking, absorb mana extruded by the stones around them. Eventually this might lead to a situation where the outer stones are half empty, whereas the inner stones are getting overcharged.

But like I said, the author most likely never thought about such things. In fact I bet the author doesn't know dynamite starts to leak nitroglycerin before long. If he did know that, he might have actually used the knowledge to do things differently, just to flex about his knowledge.

[KrayZ33]

I'm fairly sure that when dynamite was first developed, most didn't expect that if it's left to sit for some years, it would start to "sweat" or "weep" and become dangerous and unstable. It doesn't really have anything to do with how smart he is or not, apart from the lack of caution. When you have a huge pile of those magic pearls in a bag, isn't it possible they will slowly leak mana? Where does that mana go? From the outer stones, it might just disperse into the atmosphere, but what about in the very middle of the pile? The leaking mana would actually concentrate there, as we can assume mana isn't even affected by gravity to a significant effect. The stones in the middle of the pile might then, instead of leaking, absorb mana extruded by the stones around them. Eventually this might lead to a situation where the outer stones are half empty, whereas the inner stones are getting overcharged.

But like I said, the author most likely never thought about such things. In fact I bet the author doesn't know dynamite starts to leak nitroglycerin before long. If he did know that, he might have actually used the knowledge to do things differently, just to flex about his knowledge.

Considering that the family, who uses this stones for generations, felt it was save enough to give it to their daughter who is also using a lot of mana.

So I doubt there is anything wrong with them unless they break. But since he creates them, it seems they are not that complicated in the first place.

I think it does basically nothing unless you overfill it with so much mana that stone starts to break and the massive amounts of mana react violently.
If they aren't filled to the brim, nothing will happen, even if they crack or "leak".
Otherwise they wouldn't give it to their daughter and put it around her neck.

Kid falls down -> explodes(.gif)

We've all seen it happen, no one wants that.

[Kraco]

But since he creates them, it seems they are not that complicated in the first place.

The thing is, the MC dude wasn't given the recipe for the stones. He reverse engineered them. There might have been factors Dia's clan figured out over the centuries, but some dude who was only interested in using the stones the "wrong way" would be blissfully unaware of. It's not like our world would be lacking cases of cheap manufacturing countries copying originally more expensive products to flood the market with them. Typically they are inferior to the originals.