Ensure you take into account fiat deposit fees, trading fees for USDC and withdrawal/transaction fees from the wallet you deposit with along with counter-party risk.
I've used polymarket and want it to succeed, but it's not a smooth process yet.
Steps I had to follow to bet:
1. Send USDC to polymarket address
2. 'Claim' USDC when it arrives in Polymarket, but due to ETH gas fees, this function didn't work. It only works when they top up the relayer with ETH, so you can wait (as I did but it was emptied before I clicked), or pay more ETH yourself to self fund this conversion.
3. Place your bet
4. Wait for the bet to complete (to be fair, the team quickly resolved the market)
5. Withdraw the cash, this worked, although I got several errors throughout.
The best part here over other crypto based prediction markets is the resolution is quick (unlike the weeks/months augur can take), but that's due to the resolution being a centralised process, at which point, why am I bothered about using crypto at all? What's wrong with a traditional betting exchange like Betfair?
I remain convinced that rewrite was a purely anti-competitive move to stop/slow Teller and others. As someone that worked on a startup that required API access to transaction data, it was a huge pain in the ass having to write and rewrite screen-scrapers.
2. This has already occurred
3. This could happen still
4. Something about a tide going out and swimming naked