If you want to create a business that provide useful tools for portofolio management, or whatever my suggestion is only to do a market survey. Keep in mind that customer is everything so that what you call useful could be useless for others.
I have ever seen a website that have price comparison between exchange but I can't remember the name. Personally, I don't need it cause I can use manual check and sometimes I can't really believe in a platform (system errors do happen). However it could be useful if the performance is optimal.
Yes, I noticed that many additional functions and tools of crypto aggregators and media are rather conditional and useless or theyre not good enough for me to trust them. Therefore quality is everything!
So I dont want to waste my time and enthusiasm, creating low-quality useless things. I want to bet on one really useful tool. But it's pretty hard to see if my ideas are really useful or not. So now I just collect information from other users and try to understand