O.k. Let's take this to another level. Level being the operative word.
At different levels and for different purposes there are reasons to use a tsuba and reasons not to.
For most maybe the reasons for rule their thinking. That's fine.
I have seen a level of use where it was taught that the tsuba then is 'in the way', not useful. I have seen this demonstrated to various swordsmen who tried to attack his wrist. All failed. Lots of Kendo teachers included.
As such I am prepared to share what his reasoning was, and still is, from his perspective at his high level.
1) He said reliance on the tsuba breeds false security.
Now I understand this from the viewpoint of Aikido.
2) He said and demonstrated Aiki Sword, or as he called it Aiki ken as different from other sword forms and the differences were what made it what it was.
3) He said that people not understanding this could only copy 'forms' and miss the whole point.
4) He demonstrated cutting through the opponents weapon and also 'meeting' the opponents weapon, however in Aikiken he also demonstrated never to touch the opponents weapon, no 'fencing', no 'sparring' no cutting through the weapon or meeting it as that isn't Aiki ken or what he called 'true' aikiken.
5) So his way was and is Aikido ken. One move and finish.
6) Now this may take zanshin, fudoshin and even senshin but nonetheless One move based on Aikido principles and it's all over.
Now I like this and these views. The sword in Aikido should represent Aikido and it's principles I would say.
Self defence needs tsuba. Harmony needs no defence. Reaching that level may take much tsuba but I doubt it.
1) Would you care to name this allegedly high level swordsman?
2) Kendo has little to do with traditional swordsmanship that is taught in a Ryuha, so trying to imply that there is any carryover whatsoever is inaccurate (to say the least).
3) The information/opinion that you shared is (IMO) dangerous and irresponsible. If you do not believe me, then I would be happy to arrange for a teacher in a traditional Japanese Ryu to attack you with a bokken, so that you can experience for yourself, the results of your assumptions.