Don’t fall into the trap of thinking that what works for you works for everyone!
I’d rather not carry additional batteries, because of the way I travel, that’s not always the most convenient. Being able to recharge from USB or USB-C gives me a very flexible travel setup - with powerbank functionality or USB-C, all devices can charge or be charged off each other which is very useful.
Adding a small solar panel means I’m not reliant on power and the solar panel is much lighter than carrying additional cells - depends how you’re travelling, different criteria become more or less important depending on how you travel, for example, when I’m camping by car weight and dimension are less of an issue than when I’m travelling by bicycle, where weight becomes critical. Travelling by motorbike the weight and dimension is less of an issue than by car, but weight is much less issue than on the bicycle with dimension being not so critical.
Everyone has different needs, which is why there’s so many different designs 