Adjust register in games.

There are no differences. How can be different? they have the same hw!!!
Here the problem is that most of these games if done exclusively on MSX1 would have been worse. I think worse because i suspect that colecovision games were judged by coleco to avoid having published a shitty title.
this resulted in more effort from coders ....
The same does not apply to msx.

Maybe you disagree , but the real situation is different. It is known, that in the first '80 company manufactoring console like did a very high control on game quality . they would not allowed a non good looking port of a title for their console, they wanted their version to be the best of other version in order to push the sales of the console.
this is because they have full control of the titles they sell as part of the console.
If a developing company or sw house didn't a good job for a title they fired it and did not pay the work.

This was expecially true during the console crack of '82. After that console manufacturers started to be extremely severe about the game quality of a title. This was because if a poor title did not sell well for a reason and a console manufacturer was forced to retire it. And because titles were on hw carts this would have resulted in a lot of profit lost .

A similar situation simply did not exists in home computers like spectrum/cpc/c64/msx when a crappy sw title could be published even if this quality prevented a good sell result, because there was no one judging if a game worth to be published or not.

It is a well known and documented fact.

"Adjust register in games"

This topic should talk about V9938 games, why it became a "colecovision games are done better than msx ones"?

the atari VCS had inferior capabilities and console manufacturers knew this. As a result they did non expect a "Super Nintendo" Quality Game from a VCS ;-) (Obviusly). Your comparison is simply a non-sense.
Plus the recstrictions on the quality of games was only applied when, after they realized that the first titles did non sell well because of quality.

You are right.
My 2 cents about why the adjust register was not used in all scrolling MSX2 games is that with horizontal scrolling the edges of the screen move along, which looks ugly. You can cover this with sprites, but if you don't want to use any screen-splits or other tricks than you would use up a large part of your available sprites.