You could be using those roster spots more efficiently with pitching.
I would argue this. Those starting pitchers you get in the last few rounds are the inconsistent/unproven rookies or borderline WW vets. I'd rather have either a few solid core pitchers and a couple to fill out the staff or use a LIMA-type theory and go for a minimum IPs but focus on quality than I would fill my roster with low-tier and/or inconsistent SPs that can and will blow up and kill ERA & WHIP.
Those later rounds you could get Wigginton or Aurillia to help your batting as much as those crappy pitchers could help your pitching, without the similar risk of a blow-up. An 0-4 day from a hitter doesn't hurt near as much as a young pitcher giving up 6 runs in 2 1/3.
...And it's a much worse idea if you plan on using these same guys to help you on a long term basis when your starters go down. This means these largely unused guys have to be quality players -- which means you're reducing your quality of pitching at draft time
Again having better than WW bench hitters doesn't mean I draft Pujols and back him up with Konerko. It means I have guys there that won't kill me if/when someone gets hurt (as at least one of your top hitters will be hurt sometime this year). I think you can draft backups that can make a significant impact on your offense without significantly reducing your pitching.
F Lopez is going to be gone by the time you are drafting your reserve players. It doesnt make sens IMO to draft someone early to serve as a backup.
Well then use Ryan Freel, Nick Punto or someone else instead. I only used Lopez as an example because I just drafted a 12-team league where I had Utley and C Guillen but then Lopez kept falling. I eventually drafted him in the 10th round as a backup 2B/SS.
Again the point isn't that you can get superstars and leave them on the bench, but you can get value picks, potential sleepers, and later round multi-position hitters as backups instead of pitchers. I think there's just as much trade potential with hitters as there is with breakout pitchers and the hitters won't kill your ERA and WHIP because of inconsistency or while they're cutting their teeth.