The non-leaguers knocked out the Cup holders in Saturday's third round in the biggest shock in the competition's history in terms of the gap between opponents on the football pyramid.
Smethurst says there were no hard feelings from Palace in aftermath, instead the Premier League club made a generous gesture to the victors. It will mean a massive £400,000 straight into the club's coffers.
He told talkSPORT: "It's an amazing thing for Macclesfield. We do spend quite a lot because we have huge gate receipts.
"Within football, unfortunately, the better you do and the higher you move up the leagues, the worse it actually gets financially as an owner.
"Success brings other challenges because obviously your fan base want you to keep on moving up the leagues, but sometimes it's not affordable.
"This will make the club, for the next couple of years, especially with the next draw, if we're lucky enough to potentially get an away game, especially if it's a Premier League club, you can be drawing nearly up to a million pounds in funds.
"This will help us look at strengthening the squad.
"But you know what? After the performance those guys gave, you sort of question, do we actually need to?
"I think it's more about retaining some of the talent and signing up and getting a few more contracts, so they don't leave us."