Will give it another try:

1. There are certain structural oversights in Bitcoin that need to be fixed. Without fixing this altcoins will probably overtake Bitcoin in the long run.

2. SegWit has several benefits including short term higher transaction capacity, long term much higher transaction capacity through second level transactions and also safe (!) increasing of the block size. If Satoshi would design Bitcoin from scratch today he would probably do it somewhat similar to SWHF.

3. SegWit a good solution, ready for action and well tested. Even some of it's strongest opponents secretly admit it is "good" ('verified chatlogs').

4. There are two possible ways to deploy/implement SegWit, as a softfork or as a hardfork. SegWit as a hardfork would allow a slightly cleaner implementation but would also require replay protection (as the exchanges have specifically asked for lately). SWSF does not require replay protection assuming a hashrate majority. Replay protection is difficult thus SegWit as a hardfork would altogether cause more technical debt than SWSF. Also a hardfork is generally considered of higher risk and would take a longer preparation time.

5. Because of a block verification processing time vulnerability that increases quadratically with block size, increasing the block size is only possible AFTER SegWit is active and only for SegWit transactions.

6. Any alternative to SegWit SF would take at least half a year longer in implementation and testing.

7. A mining hardware manufacturer and a rich guy are trying to prevent SegWit from being activated probably because of financial incentives and power political reasons ('verified chatlogs').

8. Watching altcoins with SWSF flourish pressure from the users will become so high that Bitcoin finally will get SegWit SF, probably by the miners accepting it after all.