1. I don't need to know your golf swing. I know physics. You cannot break the laws of physics. period.
2. Clubs, green fees, bag, balls.... and you want to save the equivalent of about 3 dozen balls by eliminating the proper footwear. Sorry. I don't follow that rationale at all. Do you wear gloves? You could defy physics there too and save another $10.
I don't wear a glove - haven't for at least 15 years, so I've saved a hell of a lot more than $10.
I sometimes just don't feel like putting on my golf shoes out in the parking lot - yeah some days I'm that lazy . My scoring has never shown any correlation with what I have on my feet. I can shoot a bad round in golf shoes with brand new spikes just as often as I shoot a good round in sneakers. I usually buy cross trainers because they have a better tread pattern than any sort of court shoes, and as a result, they are pretty good on grass too.