Differences between RC lipo batteries and Li-Polymer batteries in phones/power banks?
There is no much difference in the batteries themselves, but how they are being used and handled.
RC batteries get rough usage mechanically, they can get shocks, dents and puncture damage while operating the device they are in, and careless storing by throwing them around in toolboxes and contacts getting shorted by metal objects rolling around with the batteries, etc.
Same applies to electrical usage. They get charged and discharged at their maximun current, or even beyond them, they get drained to below safe voltage levels, and may be overcharged by manually operating the chargers. The batteries don't handle that without some damage.
Sometimes the batteries or circuits they are in don't contain any battery protection circuitry to prevent improper electrical usage.
Now, normally batteries in powerbanks and phones don't get such use mechanically and electrically. The circuits often contain battery protection to prevent overcurrents and over/undervoltages.