Modern websites should insist on smallest size possible and work without JavaScript. Constrained lines with traffic limits exist. Low-end devices are still a thing.

The monthly traffic limit of my cell provider gets exhausted in around 3 days, I have 384kbps download speed for around 27 days.

Most "modern" websites take MINUTES to load. That makes lightweight sites more interesting. Some of the heavy ones are completely unusable and timeouts downloading assets that block navigation are common.