Richard,
I agree, there's no "one size fits all" answer for cell phone questions, and everyone needs to do their homework and find the best solution that works for them. I use an iPhone and although I recently got it unlocked, I'll still be travelling on a roaming plan with my home network this year. I need to be easily accessible from home for several reasons and using a local SIM just won't work for me. Having to take time to find a cell shop, choose from a variety of calling plans, register (in some countries) and top-up on a regular basis is such a nuisance and something I can't be bothered with. I prefer to have a working phone as soon as I step off the plane. In the overall budget for a large trip, the cell costs are not a huge problem.
I have used travel SIM's in the past, but their data allotments currently leave a lot to be desired. The travel SIM I used in the past provided a local access number that was mapped to the travel SIM, so I was able to forward my calls to that before leaving. Anyone calling my home number reached me via the travel SIM. The roaming plan with my home network is a bit expensive, but it sure does work well.
As you mentioned in your previous post, I tend to leave the Cellular Data blocked unless I need it and use Wi-Fi as much as possible. I always pre-arrange all my bill payments so typically don't have to do any online banking during trips. However, if that does become necessary I switch off the Wi-Fi and use LTE / 4G as that's encrypted and therefore much lower risk it can be hacked. My primary financial institution has an App, and that provides quicker and easier access than using the regular internet browser, and I can check balances without logging in.
As you've probably found, the picture is constantly changing and it's a challenge to keep up with it.