Definitely weird how transferring between different brands sometimes works better than Pixel-to-Pixel. I've run into the same frustrations with Google's "restore from backup" options not really doing what you expect. SMS Backup and Restore has saved me in a few phone upgrades, and like you said, catching all those extra spam or blocked messages is better than missing something important. The only downside is that sometimes it's a pain to sort through the mess after, especially if you have a lot of old threads or spam in Messenger.