You should never drain the hot water heater through the hot water pipes.
Always bypass first; then remove the anode. This keeps all the Calcium and Anode bits in the hot water tank where you can flush it out.
If you try to drain the hot water tank through the low point drain by opening the Pressure relief valve (or hot water tap) and letting it "glug" out, it will suck those bits into your plumbing.
When you de-winterize all that crap will be forced into your tap valves and even into your cold water lines. This could cause all kinds issues, like slow running taps and a toilet that won't flush.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW