What, do you work for Samsung or something?
I guess we can assume you work for a company that makes external batteries since you are advocating that position...
1. Removable batteries have significant armor as they may spend time out of the device
Which means they have less battery and your phone will not last as long.
This armor would have protected the battery from localized temperature spikes.
From EXTERNAL temperature spikes, which you (and Samsung) have no idea if they are the source of the issue.
2. Removable batteries contain internal thermal and current protection, and often fusible links.
I think it's funny you imagine internal batteries do not have those features also.
The connectors cannot be tightly spaced because they must allow for movement.
Why would it matter if the connectors are close? It doesn't seem to matter to ANY OTHER PHONE MAKER.
Even if a battery short were somehow possible, the battery would have protected itself rather than igniting.
And you know that how again???
3. If there are problems with the battery, it can be returned and exchanged without the device.
Which may or may not be TOTALLY IRRELEVANT to the issues that Samsung has, the only known case where lots of people had to turn back in devices.
4. If it turns out the device is defective, it can be easily shipped without the battery and the battery saved or recycled separately.
SO stupid and pointless I can't even.