Large APS-C (22.3 x 14.9 mm) sensor
Large sensor in Canon T8i ensures a good low light image quality compared to smaller sensor, and it also provide shallow depth of field and a nice blurry background when needed.
Even the smallest lens attached to this body will be a burden to carry everywhere with you. 515g
Carrying this weight all day may not be very comfortable for you. Body Thickness 76mm
With a thickness of 76mm,Canon T8i is not a pocketable camera for sure.