I can't answer for OP as I don't know his/her situation, but every time I have asked this question to other companies, the answer boils down to

"We really wanted to use a blockchain and it is the main reason why we build the company in the first place so we never questioned that choice".

Am not the parent but, for example, the Bitcoin blockchain is essentially a double-entry transaction ledger. Every transaction has to balance inputs and outputs.

If the product poster is using has that property, then perhaps is a reasonable choice.

Postgres does not have any ledger balancing primitives.

For Decimals I’m using a hash-chain. So, entries are always balanced, atomic and immutable. Not a blockchain, as there is no need for consensus, but the properties for checking integrity are all in there.

Bitcoin-like blockchains are by default triple-entry accounting: https://onlinelibrary.wiley.com/doi/abs/10.1111/acfi.12556