In my opinion, hiking boots don't provide enough ankle protection - there's no built-in rigidity there as hiking boots and shoes are expected to be light and flexible.
I was facing the same decision a few months ago. I looked at RevZilla and they offer some riding shoes or low boots, but most weren't available in my size. If you don't have large feet, you'll have a much larger selection.
I ended up buying cheap Cortec Accelerator boots that I ride in now. They are to be my 'daily beater' boot that I don't care about wearing out too fast.
Feet sweat a little, but I just wear tall wool socks and it helps control it quite a bit.
I respect your opinion because you are correct, they don't offer the same protection as motorcycle boots. The hiking boots cover the ankles with padded protection, but have no plastic insert or energy-absorbing foam material.
Most answers to the question at hand will be a compromise. Each person must select the level of compromise they are comfy with in any given circumstance.
This in no way implies that hiking boots are a substitute for motorcycle boots. Only that they may be an alternative to wear for a short commute and then all day long in a walking role. Offering some protection and quite a bit more comfort off the bike.
They would be better overall than wearing most styles of comfortable walking shoes, sandals, etc. while on the bike. They will be a little less comfy in the mall or the office.
Granted, some folks don't mind the sweaty feet and walking all day in boots not designed well for that purpose. Others, with storage, will carry a pair of walking shoes and leave their boots with the bike.
Having any ankle coverage is a world better than not. This is all that is required to participate in the MSF course. A high-top tennis shoe meets those minimum requirements.
Having padded ankle coverage is another level better than just a layer of fabric or leather.
Having armored and padded ankle coverage in a purpose-built boot is ideal, for riding. Not so much for the activities described in the OP's question.
The answer will vary from person to person and from one circumstance to another. The rider will need to evaluate the possible choices, eliminate those that don't provide any reasonable protection, then, find the compromise from the remaining choices that is most appropriate for that day's activity.
Now, we could call all the disciples to turn this into an ATGATT religious thread. If so, then, knee-high motocross boots will really be the only viable option, won't they?
I feel comfortable on a twenty minute ride on highways wearing quality hiking boots. (Still encased in a full Motoport suit, gloves and helmet) I feel even more comfortable spending the next nine hours at my desk or walking around the office doing IT work than I ever have in the Sidi Rains, or other motorcycle-specific boot.
I didn't wear hiking boots for riding the ET500 in a day, or for motorcycle vacationing, day after day. It would be neither prudent, nor appropriate.
In the end it will always be up to the individual as to what their priorities will dictate as their choice, and, choice is always better than no choice.