Money was indeed a substitute for many things in Silas Marner's life of the eponymous novel Silas Marner.
Now, this statement is much more powerful than it looks. When Silas lived in his hometown of Lantern Yard his emotional, social, and physical needs were all met.
Socially, he was an active part of his community and a member of a religious group that worshiped together.
Marner was highly thought of in that little hidden world, known to itself as the church assembling in Lantern Yard; he was believed to be a young man of exemplary life and ardent faith..
He also had friends, was engaged to marry Sarah, a girl whom he had known for quite some time.
Their engagement was known to the church, and had been recognized in the prayer-meetings...
He had a best friend in William Dane, and he was in all aspects someone fulfilled.
The problem began when William Dane betrayed Silas by framing him and falsely accusing him of theft. Since Silas had a tendency to fall into cataleptic fits during worship, William Dane (who was no good friend in the first place), decided that such fits may not be godly at all. Sarah was weary on the subject and leaving Silas would have required for the congregation to conduct an investigation. Either way, the framing ended up with Silas getting shamed out of Lantern Yard, losing his good standing, his girlfriend (William stole her), and his life as he knew it.
When he comes to Raveloe, he is basically a broken man who has to rebuild his life. The problem was that, rather than attempting to blend in and socialize, chose to isolate himself entirely and dedicate himself to his job.
As part of his isolation, comes the need to attach to something, since there is nobody to be connected with. What could be better than the money that comes out of hard work, which is also the only distraction in his life.
The livelong day he sat in his loom, his ear filled with its monotony, his eyes bent close down on the slow growth of sameness in the brownish web[...] But at night came his revelry: at night he closed his shutters, and made fast his doors, and drew forth his gold.
This is essentially what happened. Gold substituted the very things he used to have in life in terms of love, friendship, and community. It is the robbery of the gold which brings him back to normal life, after a massive meltdown that results in the entrance of Eppie in his life. That is when his life basically starts over.