The first and most obvious advantage is that, if your existing home is worth a lot of money because of its location and size, and/or you have a lot of equity in it, the sale of the home could give you a cushion of money to make life in retirement a little easier and fund some of those 'bucket list' adventures.
I'm assuming that you would be moving to a property that would be easier to manage as you get older - not one that's going to make life more difficult.(Although I accept that I could be biased because cleaning and other assorted, household-related tasks are not really on my list of fun things to do and I can't imagine that ANYONE would CHOOSE to spend MORE time engaged in those activities!)
Downsized would, presumably, mean cheaper as far as heating, cooling and property tax bands are concerned.
If you like decorating and/or DIY, you might relish the idea of 'doing up' another home and putting your personal stamp on it.
You could have a fresh start and get rid of some of the clutter and 'stuff' that you've accumulated over the years. (Although having to get rid of much-loved stuff because you can't fit it into your new place could also be a disadvantage...)
And, of course, downsizing would also bring the opportunity to look for a neighbourhood with close proximity to the amenities and services that will be useful in later life if your health deteriorates and you can no longer drive.