>If I lend my friend $10 every day for lunch and he pays me back the next day and this happens 5 days in a row in what context would it make sense to say I have lent him $50 dollars?

In a sense, kind of. If your friend is expected to be able to pay for his own lunch (because it's costly to keep covering for him) and only very sporadically need to borrow from you (because e.g. he forgot his wallet), and suddenly you find yourself doing it every day for several days at a time...

Then yes, it's worse than your friend having to "borrow $10 [once]" from you, even if it's not as bad as him having a $50 shortfall (esp since he does pay you back).

It also means your friend is making a systematic error he's not correcting, and you should probably start charging him more to, in effect, carry his money for him. If you don't, you're enabling his dependence.

Similarly, banks are expected to only very sporadically need liquidity directly from the Fed. If they need it over such long intervals, that's bad, and the daily amount borrowed, by itself, understates the significance. It also feels like the Fed isn't doing its job if the banks aren't paying (and savers aren't receiving) a premium for such an unusually scarce service.