True, but I cannot see how that relates to dudalb's point.
Then again a project to build a bridge between Scotland and Northern Ireland would face challenges if Scotland was independent and the project had been foisted on them by Boris Johnson. I suppose if the UK carried the entire cost of the project, the Scots' objections may be diminished - though a foreign country building a bridge without your consent is an interesting prospect.
Operating the bridge would be fun. Huge lorry parks would likely be required either side to accommodate the vehicles waiting for customs inspection. Then again this would be trivial compared to the problems of the land border between Scotland and England.
That said, it's pointless getting too worked up about it. This was yet another example of Boris Johnson "just saying stuff" (a la Trump

). There's no money for the scheme, little demand (at least not enough to justify that level of spend) and the engineering challenges, whilst not insurmountable, are significant. IOW - not going to happen in my lifetime.