Who are responsible for signing off on new implementations?

Why does the Hakka Finance ecosystem need multi-sig and signers?

Before we had multi-sig and three different keyholders/signers, the HAKKA token contract and treasury were held by Ping Chen, the founder of Hakka Finance. This made it easier to move quickly during the bootstrap phase but is also a single point of failure for the ecosystem. That's why there's a multi-sig wallet now which controls the admin keys to the Hakka Finance smart contract and treasury.
The multi-sig wallet is the following 0xF2B8f214Dc81b849ed3BDCAEdA6c8c39625c500A
The keyholders are as follows.
Ping is the founder of the HAKKA ecosystem, and has been involved in the Ethereum community for over 4 years as a dApp developer. He previously founded Pelith, and operated out of Pelith to provide Ethereum-related technical literature and meetups for core contributors to the ecosystem in Taipei, Taiwan. He has also been involved in the DeFi ecosystem for over a year.
Yahsin Huang is a community builder in the blockchain space. Her focus has been exploring how the democratization of digital tools empowers individuals. She is the marketing manager at Diode. She founded the RadicalxChange Taipei chapter, co-organized the Taipei Ethereum Meetup events, and contributed to several technology media outlets. Yahsin has participated in major Ethereum conference events since 2016, including DevCon in Prague, Czech Republic; EDCON in Sydney, Australia, and, more recently, EthCC in Paris, France; EthDenver in Colorado, USA. She covered Taiwan’s Maker Movement in 2014 and hundreds of open-source developer activities in 2013 as a magazine journalist. She has a bachelor’s degree in English literature from National Dong Hwa University.
Luke Wagman started his career in finance in analyst roles at Goldman Sachs and Black Rock. After being moved by the virtues of decentralization, he left Wall St. in 2016 to become the 2nd employee of the CoinMarketCap team where he served as the Chief Content Officer and the Chief Evangelist. Along with spearheading various business development and marketing efforts, Luke built the team that was responsible for evaluating and listing all the coins and exchanges as well as maintaining the several thousand datapoints across the website. Luke is also one of the best Dance Dance Revolution players in the USA!