Wait a minute. Is BU another bitcoin or just a mining software cause I thought it was a software used to mine bitcoin.
BU is just Bitcoin. It is a fork of pre-segwit core, which has been modified to allow the market dictate max block size. The first time a miner mines a block larger than 1MB, it will result in the forking of the Bitcoin chain into two. Whether or not both forks have a viable future is currently unknowable. Whichever ends up the majority fork will no doubt be considered the real Bitcoin by the world at large. The expectation among the BU community is that the BU branch will be the overwhelming winner.
Storage isn't the real concern. It's RAM (in the short term) and bandwidth (in the slightly longer run).
RAM is cheap and getting cheaper. Bandwidth is cheap and getting cheaper.
At larger blocks (hence more tps) and larger databases, SSDs will be the only way to go. You can trade SSD for RAM all you want, but the truth is that expensive resources will be needed that are not easily available. Hence, decentralization goes down the drain.
For Bitcoin to be bitcoin, we need average JOE to be able to run a full client easily.
The expectation that the future health of the network depends upon people who will not spend 0.2 BTC on their machines is ludicrous.
It's not. For BU to reach 75%, Segwit must stay at 25% and 8MB must vanish!
Well, no. 8MB will happily validate larger blocks up to the 8MB limit. That'll likely be several years of BU compatibility. IOW, 8MB is counted into the tipping point.