What was a proposed alternative to Segwit?
The proposed alternative was to increase the block size. This approach was implemented with Bitcoin cash, a hard fork of the bitcoin network chose to implement a larger block size limit rather than rely on a new transaction structure.
What did Segwit solve more than just the scaling issue?
SegWit fixed transaction malleability by removing the signature information (otherwise known as the “witness” information) and storing it outside the base transaction block. With that, signatures and scripts can be changed without affecting the transaction id.
How is Segwit and the Lightning network connected?
SegWit supports the development of second layer protocols like the lightning network. The lightning network will further boost bitcoin’s transaction capacity by taking frequent, small transactions off-chain, only settling on the bitcoin blockchain when the users are ready.
Are people, wallets and other services forced to use Segwit?
SegWit was a soft fork and compatible with the old protocol.