??? I am highly aware the Russian army has not met your standards of Fighting.
What does the world have to gain from this?
Is the death and destruction being reaped outweighed by the benefit?
My standards don't matter. The only standard that matters is
victory. Clearly the Russians failed to meet the only standard that matters with their first strategy. They still have a chance to win, so the story is not finished, but the history of that first failed stage will be studied for many years.
As to your questions, you'll have to ask Putin for the Russian answer. We can only speculate as to why he invaded, but I'm of the mind to simply believe what he has been saying consistently for the past 20 years. Which is that he intends to rebuild the glory of Russia. My personal answer is, it is probably not worth it for the Russians. Putin overreached and it will hurt. The Russian people will hurt far worse in the long run.
If your asking about western support for Ukraine in a war against Russia, then I suggest you ask the Ukrainians if it is worth the cost of blood. They keep fighting and dying to defend their country, so I'm going to go out on a limb here and say that the Ukrainians believe its worth it.
As for if it is worth a few billion to the United States to send to the Ukraine? It's chump change compared to what we spend elsewhere because of Russia.
Give the Ukrainians a few billion dollars in military equipment while we cycle out our inventories?
OR Spend dozens of billions trying to create another counter measure to whatever goofy super weapon Putin decides to build next?
Atomic cruise missile?
Deep sea intercept sub?
Extraterritorial exotic assassinations?
Anti-Satellite Rockets?
New ICBM's?
How many times does Russia attempt to breach our airspace each year?
How many weapons has he funneled to our enemies aboard?
How many nuclear attack subs do we maintain to keep a MAD option open?
How did those Russian made RPG-29's really end up in Iraq?
How many tanks and other weapons does Russia sell to African extremists?
All of those actions have a price tag associated with them that add into the tens of billions of dollars annually.... So.... Sure. Now that I think about, I'm quite content if the Ukrainians can take an old 155mm howitzer and shove it up Putin's ass.
I'm just waiting for the Georgian's to realize the occupation troops in South Ossetia have been depleted, the Japanese to take the Kuril Islands, and the people of Belarus to kick out their Putin puppet when they realize that Papa Putin is a paper tiger.
But I'm biased and my calculus might be off. I have always had a hate for commies.