I thinking to upgrade my touring bike with a hub dynamo. I currently use a tire side dynamo. It is nice but I think the hub dynamos have less rolling resistance and are a bit more powerful (more watts). In addition it is constant on and I could use it for daytime running lights instead of the battery lights I use for flashing lights right now.
I just wonder if it is worth it and if yes if I should just get the existing wheel re-spoked or just buy a new wheel. The bike is over 20 years old and so are the wheels...
Any thoughts?

Thanks and happy riding