Consider these sentences where the verb is the same as the head of the direct object, or the head of the prepositional phrase.
mi toki e toki-pona
mi toki kepeken toki-pona
mi toki e toki pona.
mi toki kepeken toki pona.
We speak (using) Toki Pona.
ona li musi e musi [ma alasa nena kiwen anpa]
ona li musi kepeken musi [ma alasa nena kiwen anpa]
ona li musi e musi Manka.
ona li musi kepeken musi Manka.
They play (using) the game Minecraft.
Many speakers find this a bit repetitive and awkward. You could also interpret the versions with e as "We say 'toki pona'" and "They entertain the game Minecraft."
In these cases, you can think of the action and the object as the same thing, so you can shorten the sentence by modifying the verb directly.
mi toki pona.
We speak well. We Toki Pona.
ona li musi [ma alasa nena kiwen anpa]
ona li musi Manka.
They play in a way named Minecraft. They're Minecrafting.
This way is generally preferred because it is more compact, and thus more pona. In fairness, these forms also have other interpretations, "I am Toki Pona" and "It is Minecraft", but this comes down to context more than phrasing.