Dont use bitcoin trough a phone because the fees are enormous. You can use almost every coin through a mobile wallet and the are over 1.4k altcoins out there, you just need to find the right one
Fees don't have anything to do if you are using mobile phone or if you are using offcial wallet provided from github that runs node. Fees are topic for themself, some mobile apps, such as coinomi will allow you to put your own fees but then they can't promise you that transaction will go through.
Fees are based on how large is your transaction ( how many inputs and outputs it has) the larger the trasnaction is in byte size the higher fee you have to pay, on the other hand since bitcoin network is loaded and not many people even use LN as from now, blocks are always full and when theres tto many transactions waiting outside to be included into blocks you have the situation where those trasnactions with higher fee make it and are included into next block. So now we have a problem since there are to many trasnactions out there and bitcoin "has problem with scaling" which is why you see fee raise as everybody else is like outbidding others in terms of fees to be included into next block.
LN should solve this at least at some level, but the problem is now that not many servieces and wallets have bulti in infrastructure for this and maybe they even don't consider it as a number one priority. LN should create how to say "second layer" over the blockchain and should provide faster trasnctions with lower fees and this works so far. But since it is not used that much we can't say if it will fix the main issue once and for all.
