I don't think those are the actual trade offs for modularity. If I want waterproofing, I use waterproofed modules and a specific case. If I need more battery life, I use a bigger battery module.
The real tradeoff is size. The ultra thin electronics are the benefit of not having modules. Related to that is performance - the performance you can get is well correlated to how nicely you can put your traces on the PCB connecting the two. Having to go through a connector adds another competing constraint
Source: have done some modular and non modular designs of the same. Not nearly to the same precision and performance requirements as building a phone, but not that far off
The real tradeoff is size. The ultra thin electronics are the benefit of not having modules. Related to that is performance - the performance you can get is well correlated to how nicely you can put your traces on the PCB connecting the two. Having to go through a connector adds another competing constraint
Source: have done some modular and non modular designs of the same. Not nearly to the same precision and performance requirements as building a phone, but not that far off