tl;dr – Can’t computers do math?
Something that has long bothered me is the fact that transferring points and miles (and purchasing them, for that matter) almost always has to be done in increments of 1,000. This is particularly annoying when you need some random number (that’s less than 1,000) of points to complete a redemption.
It feels like this shouldn’t be the case. The conventional answer is that using increments of 1000 allows airlines/hotels/travel partners and banks/credit card companies to more easily manage large volumes of points, maintain a simple transfer ratio, simplify calculations, particularly when transfer bonuses are in effect.
All of this sounds great, but this all reduces (got em!) to a machine doing math, which, from my experience, computers are pretty good at. A debit on one end, a credit (multiplied by some factor if there’s a transfer bonus) on the other end, and we should be good to go, no? Don’t banks do this all the time, like every minute of every day?

It shouldn’t matter if I’m transferring 359 points or 10,000.
Many airlines still operate on mainframes, and one might be quick to point that out as a potential issue, particularly when you’re talking about integrating with other partners that may have different (or more modern systems). That sounds decently reasonable, though, but despite their age, mainframes are critical to airlines for core functions like reservations, flight operations, and managing high volumes of transactions.
And this isn’t to say that you don’t hear about computer errors from time to time. Every now and then, there’s some Monopoly-esque ‘Bank error in your favor’ story where some Joe Schmoe checks their ATM balance and discovers an extra 2 or 3 million sitting in there.

Wahoo – Beef Jerky for everyone!

Those are few and far between.
Point transfers in any increment. My new campaign slogan.