deciding an account .
It is purely up to you and your budget of course. Personally, I think that many say it is "worth it" and it probably is - if you are on chess.com a lot. Obviously cost is a factor, but realistically I could afford it. My problem is that I want to really utilize an upgraded account to its fullest, and I feel that my chess rating needs a boost first. Ironically, I know upgrading would help me improve, but I first want to see how high I can go without "help"; the similar story applies to getting a chess coach. It would help - but I'd prefer to reach an ability higher first, so I can really benefit from an account upgrade.
Perhaps your thoughts resemble mine. I recommend the "free trial" of a week chess.com premium membership to see if you think it benefits you. I fully support this upgrading decision, but I don't quite feel I understand chess enough to really benefit from an upgrade. Maybe you feel differently, and are ready. This is a personal decision as it may be great for some (but not for others). All I can do is offer my broad experience (in how I feel) and support your decision.
I hope my thoughts help
you will get a lot out of diamond the first year especially
after the first year you could always go platinum for the unlimited tactics
however, there may be some quality of life issues associated with diamond that i am not even aware of that i would miss if i downgraded
if you have the scratch then go for it