Why don't you recommend the use of bands and chains?
Accommodating resistances are a good idea on paper, but the practice has been popularized by strong individuals who all use equipment. The popularity of chains and bands has spread throughout the powerlifting world, and lifters have had great success with them. I've seen LOTS of athletes and regular lifters shit the bed with them, though, and this is for one main reason:
The strength curve for athletes/regular guys is heavy at the bottom and light at the top, so they need more low end work. The strength curve for geared lifters is light at the bottom and heavy at the top, so more high end work is needed.
Using bands/chains on a raw lifter will lower the use of bar weight and THUS lower the amount of weight thats used at the bottom of a lift. Hence, the strength curve is all screwed up and not always suited for a raw lifter