News on April 23, according to mempool data, an empty block (i.e., a block that only contains the Coinbase block reward transaction) was mined at Bitcoin height 840421, with only a 27s interval from the previous block height. Miners pack empty blocks for economic benefits; it is their wisest choice. In order to fully utilize this time for mining and avoid conflicts with transactions packed in parent blocks, miners cannot fill transactions into blocks. That is to say, miners can only try to mine empty blocks.