It appears that Apple is trying to make its Silicon devices more exclusive and tempting to new users as some fine print on Apple's dedicated website has revealed that Intel Macs will not be able to use all of the features in macOS Monterey.
Some of those features include on-device dictation that is not time-bound, offline, on-device dictation, and neural text-to-speech voices in Finnish, Norwegian, Danish, and Swedish. The list of unsupported features further extends to more comprehensive maps of Apple Maps in cities, latest globe view of Apple Maps, Live Text, and FaceTime’s Portrait mode.
These macOS Monterey features are M1-based Mac-exclusive. However, last June, Apple did announce that it would "continue to support and release new versions of macOS for Intel-based Macs for years to come" when the company initially announced the adaptation to its custom-designed processors.
It is also not known yet whether any of these features will eventually come to Intel Macs so we'll have to see if Apple will share any update about this with its users in the future. For now, we just know that some of the main features announced will require a Mac with an M1 chip, such as a Mac mini, 13-inch Macbook Pro, any Mackbook Air, and iMac launched since November 2020.