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No the energy spent on bitcoin mining is not securing the coin.
The Top 4 Mining Pool Operators are Securing Bitcoin,
as they control more than 51% for years no matter what the individual miners waste on electricity.
Their "waste" of electricity still collectively help secure the network. They obviously don't see it as a waste (or a problem, even) either, otherwise they'd just be turning their miners off.
Bitcoin is broken, which is always apparent when transactions increase and the fees skyrocket.
Which the way users handle now is to just stop using it , until fees decrease, that is in no way a reliable service for global finance.
Bitcoin is a work in progress, and the "reliable service for global finance" is planned to be provided by layer two solutions. It sucks that those solutions aren't ready for prime time yet, but I could understand not wanting to take unnecessary risks with bandaid solutions -- I don't even want to place proof of stake under that umbrella, because again, it has its own set of problems, and implementing it will be yet another catalyst in splitting the community.