Definitely worth applying but you need to really get to know the activities and exactly what they involve as far as the DWP are concerned. PIP info is a good website for that, or try and get a welfare rights advisor or contact a charity that covers your condition(s) as suggested above. You need to be affected in a manner covered by a particular descriptor more than 50% of the time to score points. Also as above, whether or not you can do the activities reliably, safely, within a reasonable timeframe, and as often as required, can be crucial.
Being physically unable to get out of bed is not covered by any of the descriptors. Amazingly. The mobility question that deals with moving around is concerned only with your ability to stand and walk on at least one biological foot on even, mostly flat ground outside. So not being able to manage stairs, for example, or move around in your home, is irrelevant.
In terms of daily living, they want you to imagine that you are in whatever room trying to do each activity even on days when you can't. So again, even though not being able to get out of bed on a given day literally stops you from (for example) preparing food because you can't get to the kitchen, they don't give a shit. Not saying that's how you'd answer that question, but I've seen people querying this sort of thing on disability forums and wondering why they didn't score points. DWP's idea of preparing a meal involves meat and veg, chopping and peeling the fresh ingredients, and cooking at waist height (so on hob or in microwave). They don't care if you typically cook your food in the oven and can't bend down to put it in, and they (stupidly!) don't consider moving the food, heavy pans, plated meal, etc from place to place in the act of cooking.
If you can get medical or occupational health evidence that backs up your own descriptions of difficulties you have in each area, that is the most useful. Letters confirming diagnosis probably less so. I've never sent in any medical evidence in 18 years of claiming sickness and disability benefits and never had to challenge a decision. Understanding what the questions are asking and being able to answer them with detailed accounts and specific examples of struggles I've had is the way I always go.