Life's too short indeed, agreed, you'd never notice the tiny difference as you are not using ATM.
I'm wasting 3% speed by using 1500 byte IP MRU / MTU with PPPoEoA (ADSL2) with my Dlink modems, compared to the optimum of 1492 IPPDUs because that plus other protocols’ overhead fits exactly into an integer number of ATM cells. If 1492 turns out to causes no known problems out on the internet with stupid networks and servers, then perhaps I should go over to 1492.
It would be nice to get rid of ATM some day and just lose all the crazy overhead of >(48+5)/48 + plus the AAL5 CPCS trailer + cell-padding, which is >10% speed just gone down the toilet. In fact, people need to remember that about eg FTTC or anything non-ATM-based, that at the exact same DSL sync rate you just get an extra min 10% speed for free with FTTC compared with eg ADSL2+. Typically 10-13% depending on packet size. (But of course it could be ~100% inefficiency for short packets. For VoIP the ATM overhead is typically huge.) Someone who has the option of FTTC on a really long line, long for VDSL2 anyway, might be trying to compare claimed speed with ADSL2+ based on sync speeds without thinking about the >10-13% wasted.