To understand why people searched for Doraemon in 3GP, you have to understand the technology of the time. Developed by the 3rd Generation Partnership Project (3GPP), the was explicitly designed for 3G mobile phones.
While high-definition streaming is standard now, (3rd Generation Partnership Project) are still highly sought after, especially for fans with:
While looking back at 3GP files brings a wave of nostalgia, trying to watch Doraemon in this format on modern hardware highlights how far technology has come.