It's all preference and cost-benefit analysis that is unique to each person. The bands are great if you plan use the pool or water slides. Rather than leaving the keycard "hidden" somewhere, you just wear the band. I personally like it, though we go to Disney parks every year so it works out. I've never worn a lanyard (20+ cruises) and never would. I hoped for the magic bands on cruise ships for a long time and have been happy the few times we've already cruised with them. So much easier to wear a band. But if you are a lanyard person that would work too.
With that said, if you don't cruise or visit Disney often, the price probably isn't worth it. Charging it does add another level of stuff (phones, watches, bands, etc) plugged in the room, which can be a hassle if you have a lot of people in a cabin. You will still have a key card because it is unlikely ports will ever get technology to read a band. Also, you do have to give it up sometimes (most notably bars) to pay for stuff. But, that is the same for the keycard, so it's not really a change.