I have ketone strips on prescription (although it remains to be seen if I have to convince the new surgery to prescribe them 😱). My argument was that, if I really needed to test for ketones I would need a very accurate way of measuring them, which urine strips don't provide (for me - it may be a personal thing). As Mike says, urine strips have an even shorter shelf life so you can end up throwing most of them away, whereas if you are actually ill you will definitely get through all the blood strips 😱 Yes, I need them very rarely - in fact I have only been really ill once, in 2012, and really needed them at the time in order to know just how critical my illness might be, and whether I was at risk of DKA. I was, at the time, but this didn't help me get the help I needed from the NHS, but that's another story - at least I was alert to the situation, and I was very thankful I had them.
The strips can still be used beyond their use-by date, although obviously they may lose some of their accuracy. My previous surgery had a habit of wrongly prescribing the ketone strips when I requested Optium glucose strips, so I ended up with quite a supply at one time - I had to start putting an explicit note on the prescription request for KETONE strips 🙄 Yes, it can be wasteful, as it can with urine strips, but if you fall suddenly ill trying to get some from your surgery could take too long for it to be useful.