It's a very easy conversion. 1000bits = 1mB. When you look at your balance just imagine the comma that seperates the thousands from the hundreds is a period. Thus, 73,932 bits = 73.932mB.
That's a good tip and it does help to have a rule of thumb in your head to convert. If I imagine that thousands of "bits" are mBTC I can sorta get by. Still, it doesn't explain why this website invents a new and obnoxious unit and won't let us set the right units in our preferences. I mean, we're logged in, and a computer does unit conversions better than people (even rules of thumb), why not just fix this one embarrassing part of this website when it seems so easy to fix.
Well actually bits are used by many websites not only that one, they didnt really invent the term