In a computerchess-forum a user wrote this:
"There are the guys who do rating lists. They have become pretty scientific (loads of games, careful setup). 
Which means - they are basically doing the same kind of tests the developers are doing themselves.
The guys who still do long games and actually look at them are more like wine connoisseurs - they do it 
for their personal enjoyment."

So, why do I do my testings in the way they are done today?

I do my "pretty scientific (loads of games, careful setup)" with my UHO-Top15 Ratinglist. Each engine 
plays 15000 games (15 opponents * 1000 games). But that does not mean, that I do not look at any games 
or do not enjoy them. But to do so, I needed to write some tools, to filter the interesting games out of 
the huge amount of games. But, I managed to do my Interesting Wins Search Tool and now, I filter the 
games very fast and find the best ones. And I sent some of these games (and some, I filtered out of the 
Blitz and Bullet enginegames on chesscom) to the german Youtuber TheBigGreek (just 2 examples here):
https://youtu.be/_XbDLQZPEfo?si=2w9tWpWx9oD0DGHS
https://youtu.be/JleRxjFRRIU?si=JGQNjq_bJY8TPUUJ

And part of the truth is: Really spectacular enginegames are rare. And this means, the more enginegames 
you have, the more spectacular games you will get. And the probability of seeing a spectacular game "live", 
when a enginematch is running, is very small.
So, my conclusion here is: Play many, many enginegames, the more the better. And filter them, to find the 
really cool games. My tools will do the work for you and they are very, very fast! And much enginegames 
means (additionally), you get better and reliable statistics.

So, for me, there is today absolutely no reason to play slow enginegames and watch them live. You will 
see only a few cool games (most of them are high-level chess, but boring) and get no proper statistics 
out of the games. And the higher chess-level, using longer thinking-times, does absolutely not matter, 
because top enginechess is so far beyond all human chess-skills, that +50 or +100 Elo gaining with long 
thinking-times, are meaningless for any human, watching these enginegames.