This is a very good strategy if you want low variance winnings, like if you're trying to grind your first buy-in for (say) NL2 from
freerolls exclusively, without deposits. However, I'd advise against it if you're not in this position and are fine with a bit of variance. Since the field is so soft, your ROI (well, more like return on
time than return on
investment in freerolls) will be much higher if you play from the beginning of the tournament, even playing basic ABC poker.
The same goes for other freerolls which have a long late registration period and reward much of the player pool.