Delayed Blast Fireball has a unique clause about physically grabbing and throwing the spell itself:
If the glowing bead is touched before the interval has expired, the creature touching it must make a Dexterity saving throw. On a failed save, the spell ends immediately, causing the bead to erupt in flame. On a successful save, the creature can throw the bead up to 40 feet. When it strikes a creature or a solid object, the spell ends, and the bead explodes.
Casually, I've always assumed that this clause exists to act as some sort of counterplay to the mage casting Delayed Blast Fireball - the mage starts growing this ball of flame next to the party, the dextrous rogue decides to wing it and grab the bead, heroically beating the Dex Save and immolating the mage with his own spell.
Except this scenario would never realistically happen - a caster can end his concentration at any time possible, so as soon as he sees the rogue beat the Dex Save, he can just release concentration.
So why does Delayed Blast Fireball have this specific property?
I cant see this being utilized offensively by the mage himself, since wizards usually have pretty low Dex, and it would be pretty anticlimactic/humiliating to blow yourself after charging up this bomb.