The game is on many home console/handheld gaming devices/PC that plays it far better.
What's your reason for wanting to play it on mobile?
(If you really want to play it on mobile so badly I'm sure you can find a PS1 emulator app that plays the game better then the official mobile version)
i like to play some time on the phone when i'm not at home and a little time. purchased already final fantasy VI and chaos rings 3 and liked it to playing them on my phone, but i'm not sure about ff VII
Well there's other devices that play the game better BUT if phone is the platform that suits you best then you should go for it. There may be some bugs and what not that may not run as well as you may like compared to the original but it definitely wont be bad enough that'll make you not want to keep playing.
So you should definitely buy it for your mobile and enjoy the hell out of it! :)