Multiple daily readings and general reliability

Nope... but I find it reliable. I weigh myself, in the mornings, right after I wake up and take care of business. That is how I try and keep things as constant as I can. I have three older other scales at home and they all read with in half a pound of the Garmin one so I am pleased with it.

I believe the answer to your first question is: No and I don't know of any work arounds. But for your second question, I am really happy with the accuracy (wifi struggles a bit though). I have been visiting a dietician who has been weighing me and analysing my body with an InBody 260 and my Garmin Index Scales are giving me the same compositions as the InBody scales.

I would like to see this option to see multiple times over the day

You CAN weigh yourself multiple times per day, but only the most recent value is retained. I regularly weigh myself before and after activity as it's interesting to see how the weight and fat % changes. But only the latter (lower in this case) figure is retained.

It would be nice if it could log multiple weights on the same day, but this is an issue with the cloud-based 'Connect' database and nothing to do with the scales.

Not having it record multiple times a day is a show stopper for me. I was just about ready to replace my withings scale with this when I realized this limitation. I weigh my self first thing every morning so I have a consistent data point. But then I'll often weigh my self before and after workouts to see how much fluid I'm losing. If it's this final number that gets recorded for the day, it's pretty much useless as I can easily lose 5+ pounds during a long run in the heat even when drinking 24oz an hour.

With the withings, I have all of those data points to look back on.

Hopefully Garmin will add this functionality at some point.

I wouldn't expect them to add this feature as it has been some bugs related to fat mass they never bothered to fix.