You can't get tail emission right. A good TE value in a certain market conditions is an awful TE in different market conditions. The success of tail emission depends entirely on whether the number of miners stay almost-constant thoughout the lifetime on the coin. Just like in economics, there is a break-even point in the number of miners where more miners joining the network will not see an increased reward - as the price (which is dependent on users buying and selling) works independently from miners.

By supplying Tail Emission you constrain the network to a certain number of miners, and since there is no noticeable increase in hashrate, there is no corresponding increase in coin scarcity either, hence no price increase - miners will have to support themselves on a block reward (i.e. TE value) which has a fixed USD value forever.

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I don't like BMM not because of any technical problems with it, but for a political reason - it will confirm the association of bitcoin with other shitcoins, on a protocol level [bad press confirmed].