I have been both a backpacker and a bicycle tourist since the early seventies. Some equipment is suitable for both endeavors and some is not. Low weight is important for both but the main difference IMO is that volume is much more important on the bike where wind drag is a factor. A good example is a closed cell foam pad. It's light, simple and bombproof but I wouldn't dream of using one for bike touring because of its volume. Inflatables are preferable because the average bike pannier is not nearly as large as even a small backpack. Along that line of reasoning I would choose down over synthetic because it packs down smaller for the same warmth.

There are a lot of things I take backpacking that just aren't needed for bicycle touring e.g. compass, hiking poles, gaiters, blister kit, etc. Bike touring keeps you generally closer to civilization and you will rarely have to carry more than a day's worth of food. That keeps my bag size down as well.

Anyone who thinks a wood stove and chimney are practical for bicycle touring clearly has never done it.