R2000 and R3000 for printing only color and Glossy

[EinstStein]

R2000/Hi-Glossy2 is good for glossy paper and color, but not  for matt or B&W.
R3000/K3 is more flexible, good for matt and B&W too.

But if I can live with only color and glossy, what's the disadvantage with R3000/K3?

Concerns on  R3000/K3:               I know I'd waste the Matt-black ink, as it will be outdated in 6 months (life once opened), but what if I don't put it on until I really want to use it?
Concerns on  R2000/Hi-Glossy2:    It seems R2000 is the only printer still using H-Glossy2, Would Epson discontinue this line soon?

[kjkahn]

...
I know I'd waste the Matt-black ink, as it will be outdated in 6 months (life once opened), but what if I don't put it on until I really want to use it? ...

According to p.43 of the printed manual for the R3000, "... both must be installed for the printer to work."

[slackercruster]

R 2000 does matte color nice

For BW, most of the time you must tone it with the 2000.