DR makes power flow more smoothly. Currently, incumbent parties and politicians can maintain a monopolistic grip on government for decades at a time. When they fall, government can change course drastically. With DR, power changes would be gradual, and power would be more fairly shared. DR makes legislators' jobs easier.
Legislators currently represent arbitrary, large, diverse districts.
With DR, all of a legislator's constituents would share common interests. There would be no frantic, vicious campaign every few years, and much less fundraising would be required because campaigns would be carefully targeted.