As a former professional I can confirm that these opportunities are mostly real and worth taking advantage of if you are confident you will never want to engage in serious sports betting (if you are going to be serious you want to ensure you are using a friendly person’s referral code if possible, so you collect their affiliate payments at least in part, which could be worth more than the bonuses).
Also, you can simply use pinnaclesports.com as a reference ‘fair price’ for all wagers, and assume the middle of their market is the true odds of everything, and you won’t be that wrong.
Echoing others that there’s already a bunch of conversation on LW, so that’s probably going to be the primary comment thread. I’ll still try to check back periodically to see if there’s anything distinct here.