In PPR it can work just fine.
There are a few teams where it might make sense, depending on the value:
DAL - Dez and Miles
NEP - Welker and Brandon
NYG - Hakeem and Salsa
GBP - Jennings and Jordy
ATL - Roddy and Julio
PIT - Wallace and Antonio
DEN - Decker and Demarius
NYJ - Santonio and Cromartie
Granted, in some of these cases, it's not likely you would end up with both since they're ranked close together.
But I've done it in the past. It never seemed to hurt me.
A couple years ago I routinely started Wayne and Garcon among my 4 WRs. In a way it was good because I didn't have to worry about deciding between them. If one went off and the other didn't, it was OK. At that time they tended to sort of trade off as the go-to guy.
12-tm PPR: QB/RB/3WR/2FLEX/TE/D-ST-PK [FAAB]
Latavius/Washington, Smallwood, Booker, Rawls, Dion
Antonio, Nuk, TY, JMatt, Royal, Moncrief, Coleman
NEP DSTPK (inc. Gostkowski)
Keepers: Reed, Rawls