Microsoft Gaming CEO Phil Spencer has shared new commentary around play-to-earn game mechanics and NFTs, saying he feels “cautious” but doesn’t want to write off any new technology.

Speaking to Bloomberg, Spencer said the “play-to-earn” category specifically gives him pause. He admitted that this isn’t new in the gaming landscape–people have been gold-farming for years–but such mechanics being built directly into games represents a new step that requires a cautious outlook, he said.

“Play-to-earn specifically is something I am cautious about. It creates a worker force out of players for certain players to monetize. To be fair for us, in the games industry, this has existed for years and years. There have been gold farmers–people who literally just spend their time doing some menial task in a game to accrue some currency that they can then sell to some other rich player for real money, so that person doesn’t have to spend their time,” he said. “But now you find games that are starting to build that into the economy of the game itself.”