I agree with Sahar, the carrier is extremely useful if you're traveling by plane. The car seat plus stroller means u can take Uber rides etc
I travelled with our 4 month old without my spouse and definitely made use of both. Checked the stroller at the gate (they will have it waiting for you when you land) and used carrier for boarding and getting off until I was at stroller again.
Carrier for layovers as I didn't get my stroller back until luggage pickup at my final destination. I traveled alone with my 4.5 yr old on two long haul flights with layover in between. Stroller you will need at final destination. Can also msg me personally of you have any other questions.
@Darshita sure will message you
Carrier is a great option to keep baby distracted for a long time. However, I definitely recommend having the stroller with car seat in case baby gets super sleepy!