Thomas R. answered 06/23/19
Over 25 years of experience and a sense of humor about math
What you are missing is that most of the people involved in the conspiracy were profoundly incompetent. The burglars had a lookout, but they feared their walkie-talkies would alert someone and so turned off the volume. When guards arrived, they were beyond reach and got caught. When the judge questioned them, they gave their profession as "anti-communist" . That reply is what drew Woodward's attention in the first place.
Anyway, the money was not to be planted. To this day, no one has been able to prove what they were planning to do in the DNC HQ. We do know this was not their first visit; they had planted recording devices the last time, and returned to retrieve them, but we have had no official acknowledgement of what they heard or even where the recordings are now.
When G. Gordon Liddy and his buddies broke into the offices of Daniel Elsberg's psychiatrist later on, they borrowed a camera from the C.I.A., intending to photograph documents. However, they also took selfies of their team smiling as they picked the lock and snuck in. Then, in a burst of genius, they forgot and left the film in the camera when they returned it to the Agency. As soon as they developed it and saw what had happened, the C.I.A. reported this to the authorities and had proof from the break-in team themselves to back it up.
If you would like to learn more, try reading All the President's Men, which tells a more complicated story than the very good movie had time to do. You might also enjoy reading the uncensored transcripts of Nixon's tapes -- not the heavily edited ones he provided, which made him look like a harmless little angel, and not the guy who kept trying to throw subordinates under the bus, which scared them into testifying against him.