The upgrade’s relevance has been widely noted, and crypto-focused research firm Arcane Research stressed that it is “arguably the most important and anticipated upgrade to the Bitcoin network” since Segregated Witness .
“The improvements in privacy and efficiency come from the fact that the spender of a MAST output does not have to reveal all the scripts, only the one they used.
It is a new form of script that removes the 10,000-byte size limit, thus giving Bitcoin smart contracts more flexibility, and it enables scripts that are only partially executed to have the rest of their execution code hidden until it is used.
Arcane Research stated that, like any other, this upgrade too carries some risks.