Yeps. When I insert the micro SD card, I can choose to format it as internal storage which merges the mSD card storage with the internal storage capacity. This is also the reason why I didn't buy the 4GB RAM with 64G storage since I've got a spare mSD card. Not worth paying the extra money for just 1GB RAM.
I wonder what's the difference between formatting it as internal storage and using it as an external storage apart from not being able to use the mSD on other devices. Will formatting as internal storage boost the reading speed?
Update:
I googled a bit and found the answers to my questions.
Source:
https://fossbytes.com/android-sd-card-internal-storage-adoptable-storage/
Some important things to consider
SD cards are slow
This is the painful reality of these tiny memory chips. Even though they can store tons of data, they’re slower than the internal storage and have a limited number of read-write cycles.
Using SD card as a permanent storage would require more frequent read/write operation, and it would degrade its performance over time.
Android does a performance benchmark of your SD card to make sure it’s fast enough to match the internal memory.
It warns about the performance of the external storage and may even decline to adopt if the SD card is extremely slow.
Your Android will literally adopt the storage
With Adoptable Storage, Android encrypts the external SD card being used as an internal storage, thus, it gets tied to a specific Android device. The key used to encrypt the data on the SD card is stored on the Android device’s internal memory. So,
it is not possible to mount an adopted storage to another device because of its encrypted nature.
However, you can remove the storage from your device and put it back on. The device will remember the details about the apps installed on the adopted SD card to reverse the settings with the adopted storage is connected later on. This way you can use another SD card also.
Always make sure, you don’t remove the adopted SD card without following the unmount procedure, otherwise, the storage media might get corrupted.
How to make the SD card portable again?
If you want, you can roll back the changes made by the Adoptable Storage feature. Follow the steps mentioned below:
Redo the option to: Format SD card as internal then tap Format. Now, you can use the SD card as portable storage and mount it on any other Android device.