Valve did not want coaches at all and was quiet for many years until teams started to rely heavily on them. Remember how NIP with THREAT started doing much better until valve changed the rules? Or how NAVI kicked seized from IGL because they were about to rely on their coach, only for Valve to step in and force to have seized back? This is what made them intervene and change the rule to only allow coaches to talk during timeouts when teams started to rely more on their coaches, allowing certain teams to have advantages over others. As a middle ground of allowing coaches and removing them completely.

From what I understand, Valve is now making players choose between allowing coaches to always be allowed in the server at all times (like before, always talking/watching, not just during time-outs), or no coaches at all (not even during timeouts), but...

Should even one team vote for the second option, coaches will not be allowed to participate.

This to me is just Valve making its decision to not allow coaches at all, as the chances of a single lower tier-team voting no-coaches are very high. This is close to not having a vote at all.

Having a coach at all times makes the players focus more on the game, and essentially having an extra fragger as the IGL is split between organizing his team and playing the game. We seen many IGL leave their IGL roles, and perform much better as a regular player, so this is something that makes me want to have coaches all the time (From a spectator point of view).

But, I agree with Valve that it sort of defeats the basic gameplay of 5v5 games that regular plebs like us play. Having a coach would change the meta too much that playing "pro" and playing "regular" matches would play much differently.

Does any other game have/allow coaches during matches? I do not watch other games to know.