You should consider how much risk you are willing to take and how likely it is that you will get a smaller (or larger) than expected bonus.
Using the pathological case to prove your point rather than a more likely case is disingenuous at best.
I'm talking about people trying to make an honest living, and having to deal with nests of vipers while trying get reasonably compensated.
If market is 104k, don't offer me 52k salary + 52k bonus, because I have to say I make 52, not 104 - well below market.
To me it sounds like a way to artificially deflate salaries (not specifically compensation. Your SO might want to know how much you expect to make all year, but for budgeting purposes, there's a big difference in budgeting for a 1k per week cash flow and a 2k per week cash flow.
When you are comparing your current compensation package to the industry standard the better one is the one that is worth more to you. You might put an unusually high or low value on risk or the cost of delaying compensation till the end of the year. You might value the free lunches or health insurance more or less than the average worker. Since you are the one receiving the compensation package what matters is what it is worth to you.
The bottom line is that market rate is total compensation, not just salary. If a company offers you a 'market rate' salary with no bonus and no benefits then that offer is bellow market rate. If an offer has lower salary, but great benefits and a huge bonus then (if you will actually get the bonus) that offer is above market rate.
In my case, a bonus is extra pay, usually tied to performance (individual or corporate), while yours appears to be 'another category of compensation for work done.'
Companies may withhold a higher percentage than a standard paycheck, but this is generally because they treat the bonus as if you will continue to receive that income throughout the entire year, and withhold at the corresponding higher rate. When taxes are filed you will receive a refund for any taxes overpaid.
