"why it became a "colecovision games are done better than msx ones"?
So far I found these games have smooth scrolling via adjust register:
Psycho World, Hydefos, Higemaru, Chuka Taisen, Space Manbow and Golvellius 2/Super Cooks
That's 6 (or 7) and possibly more.
Now for the games (only classic JP developed and excluding games like USAS, Mon Mon Monster and Yuurei Kun that don't have another version) that scroll, or should scroll, but don't do it smoothly:
Super Runner and Valis 2 scroll in 8 block increments. But the games move fast, so it is not necessary to use smooth scroll (and X68K Valis 2 also moves 8pixel/frame).
Gambare Goemon is a flip screen in the MSX2 version and a scroller in the FC version. IMHO the game is still OK.
I don't remember which games are PC-88 ports, but I believe most of those games use tiny scrolling windows with gigantic huds and are mostly RPG.
That leaves:
Project A2
Ninja Kun
Dragon Buster
YS (the SMS version has smooth scroll)
Rastan
and
Contra !
That's 6 games, but I've surely left out some significant game.
IMHO 50% isn't a minor percentage.
Ehm, saying that Valis 2 moves fast with its 4 fps on a standard msx is a bit too optimistic ;-)
The player sprite is either still or running full stride, hence no need to slowly scroll the screen:
1 character block/frame is OK. 
Moreover, checking YT videos of the game on frame advance, I see 8~15 Fps (on TR a constant 15fps ).
