Personally I would stick to completing the main game before you worry about the master trials. The problem with having a 60dmg sword that never breaks or requires "resting" is that the whole game would just be a really easy hack and slash. You wouldn't have to think about how to approach anything.
I disagree. For one, the sword still runs out of power and must rest before being usable again (confirmed this myself by using it yesterday). It does have more durability for sure - basically like the durability it had when fighting Guardians.
For me the Master Sword upgrade was a must simply because it is the Master Sword and its original version was insultingly crap for the legendary blade. I cannot help but feel the upgrade is exactly how the sword was always intended to be, but by keeping it crap originally it gave them room to have this Trial as a DLC
Even with the upgrade, it is still a 1h weapon, so there are many times you would rather use a 2her (especially for the far superior charged attack).
Finally, even when upgraded, it is not actually the best blade available - 3 set Guardian gear, Guardian weapons with +3Attack foods (which last 30 mins a pop if made right) gives a stronger weapon than the Master Sword + Barbarian gear (as +attack food does not stack with that gear).
So, the upgraded sword is useful, it can mean changing weapons less often (but in reality, weapons are not exactly a hard ship and there are still many situations where you may prefer 2h or lance), it does look cool and certainly feels right running around with it as much as possible.
Prior to the upgrade, I have never been in a situation where I did not have 'the right tool for the job' when it came to combat, at least not since early game, well before you could even get the Sword.
In fact, really the best thing about the upgraded sword aside from looking cool, is the fact I don't need to stockpile the Lynel weapons as much (which are 58 dam weapons, so pretty much on par with the sword)
