US Citizens are required to utilize a US passport to enter and leave the United States, so if you become a US citizen you will need a US passport if you will be traveling to the US.

Also, as a US citizen, you'll be required to file US taxes every year and fill out a goddamned TD F 90-22.1 form declaring all your foreign accounts (if you have more than $10,000 US in them in aggregate for even one second in a calendar year). You'll be subject to estate taxes, and will be required to file all kinds of idiotic forms if you have a controlling interest in a foreign company or partnership or if you settle a foreign trust.

Why anyone would choose to put this type of millstone around their neck voluntarily when they are already are a citizenship in a 1st world country is sort of a mystery.