To those who regularly read on mobile devices/tablets: Is a separate kindle actually worth buying?

Ebooks are not a problem for me, I read ebooks 100x the number of physical books these days. That being said, I already read almost exclusively on my cell phone. I have a tablet, but it's the size of a small-medium laptop and it's a bit bulky for me, so I only use it if my phone dies and I'm too impatient to wait until it charges or similar reasons.

For similar readers, do you actually use the Kindle enough to justify the price tag? Do you still read on on your cellphone? It's not necessarily a need for me, because I am reading very frequently on my phone, but I would like one. I want to make sure I'm not just chasing a good feeling by convincing myself that this is a good purchase for myself and not just an excuse to spend money.