Kayaks are definitely fun.
But by the time you load and unload them from your car, drive to a lake, then reverise the process when you are done, then it can be a significant time commitment for not all that much time paddling.
Personally, I would think about it as a way to be active on weekends, rather than a regular form of exercise.
However, if you have ready access to a lake, and can (realistically) see yourself taking a kayak out most weekends (and possibly even late afternoon/evening) over summer, then that may change things somewhat.
And of course, kayaking is a great way to get out in nature, destress for a while and recharge your mental batteries. And looking after your mental health is just as important as looking after your physical health.