In order to gain, upon attaining godhood, power strong enough to surpass Tierra, an established Godhood Attainer, Voldemort used Bhutan's Primordial Philosopher's Stone Temple, Hogwarts in the Scottish Highlands, and Cameroon Volcano as the three vertices for placing the pillars.
This also revealed Voldemort's grandiose nature—or rather, his extreme sense of ceremony—
As for Hogwarts, the wizarding school in the Scottish Highlands, Voldemort regarded it as his starting point and foundation. There, he had spent his childhood, learned his first spells, and cultivated his skills and ambitions. Thus, he decided to place his childhood pillar, along with the Pillar Copper representing the Material Dimension, in that sacred place, commemorating his past while laying the groundwork for his future great undertaking.
However, as he grew older and accumulated experience, Voldemort realized that relying solely on eloquence and appearance could not win him absolute power.
He knew well that only strength could bring true rule. Thus, he chose to place his younger self, along with the Flowing Silver, in Bhutan's Primordial Philosopher's Stone Temple.
It represented his immature side—his past recklessness and pursuit of superficial fame. But fortunately, he had awakened to the truth. From then on, he learned the most important lesson in life—
Only absolute strength could bring absolute power.
As for Cameroon Volcano, it had been chosen as the final vertex of the Godhood Triangle. Though this decision might have seemed somewhat arbitrary, for Voldemort, it was a helpless choice. He had to ensure the perfection of the Godhood Triangle. Either it lay within Cameroon, or the final vertex would have to fall on the permafrost within Russia, in which case most of the region covered by his Godhood Triangle would be barren wasteland.
That would not benefit his plans.
But it did not matter. It did not matter.