Valorant community started asking why Riot implemented, Radianite, a currency in battle pass that requires more spending and the devs finally answered.
There are two types of currency in Valorant - Valorant Points (VP) and Radianite. VP is used for purchasing skins and battle pass itself while Radianite is used for upgrading purchased skins. In other words, the latter is useless without the former, which is paid for with real money.
Now, Valorant's battle pass contains Radianite but not VP, which just remains useless in players' inventory unless they purchase some of the expensive skins from the store. This prompted the community to ask why this is the case and Riot finally answered in an Ask Valorant post.
According to Joe Lee, the revenue lead for the game, the team straight up doesn't want players to earn VP through battle pass because they want to sell subsequent passes at full price.
This explanation doesn't really account for the fact that battle pass could be sold directly for real-life currency or simply a third virtual currency in the game. This approach would ensure players don't use gained VP to buy subsequent passes while the players could actually have a useful currency in their pocket and eventually buy other skins when they accrue enough.
Lee also noted that Radianite is meant to be just an "evolving currency", meaning it will be used to evolve skins, sprays and player cards or purchasing new gun buddies. These are long-term plans though and it will remain just a way to evolve skins for the time being.
This is the short version of the answer but you can check out the linked post for Lee's exact wording.