With roadmap decisions like these, the compute or storage cost for the data is an insignificant part of the product decision making.
The real cost of doing something like this is doing user research to figure out the set of human behaviors around the memorialization process, deciding where in the product to make the functionality available, training material for how it escalates up to human support teams, and what other things are on the team's plate at the same time.
The real cost of doing something like this is doing user research to figure out the set of human behaviors around the memorialization process, deciding where in the product to make the functionality available, training material for how it escalates up to human support teams, and what other things are on the team's plate at the same time.