This low level of beamstrahlung provides several advantages, some examples of which are given below.
\begin{itemize}
\item Beamstrahlung is a macroscopic effect that cannot be predicted from first principles, and the resulting beam-energy spectrum needs to be measured in situ, with significant statistical and systematic uncertainties. The measurement of observables relying on a precise beam-energy knowledge (e.g., Z or W masses, Z width, top quark mass, etc.)  therefore profit from the relative absence of beamstrahlung. Similarly, cross sections with a rapid variation as a function of the centre-of-mass energy (e.g., at the Z pole, or at the WW and $\ttbar$ thresholds, as shown for example in Fig.~\ref{fig:ttbar} of Section~\ref{sec:EWSB}) are {\it (i)} maximal; and {\it (ii)} calculable with very good accuracy, leading to small statistical and systematic uncertainties if beamstrahlung effects can be neglected.
\item The forward region of a TLEP detector is free of beamstrahlung photons, which in turn eases both the design of a luminometer and the integrated luminosity measurement. Likewise, the beam-related backgrounds (disrupted beams, photons, $\epem$ pairs) originating from beamstrahlung are small, and so are the parasitic $\gamma\gamma$ collisions. Pile-up interactions are therefore negligible.
\item Final states with photons (e.g., ${\rm H} \to \gamma\gamma$, ${\rm H \to Z}\gamma$, or $\epem \to {\rm Z}\gamma \to \nnbar\gamma$) can be selected with optimal purity.  
\item The quasi-absence of beamstrahlung photons along the beam axis (in both directions) enables an optimal use of energy and momentum constraints in kinematic fits.
\end{itemize} 
In summary, the known assets of $\epem$ collisions -- cleanliness, calculability, numerous kinematic constraints, and absence of pile-up collisions -- are well preserved at TLEP, mostly because of the absence of beamstrahlung. When it comes to precision measurements, these advantages come in order of importance right after the large integrated luminosity. 