Combining prayer for a valid excuse

بِسۡمِ ٱللَّهِ ٱلرَّحۡمَٰنِ ٱلرَّحِيمِ
In the Name of Allah, the Most Merciful, the Bestower of Mercy

After reading chapter 99 in Sahih Muslim on "COMBINATION OF PRAYERS, WHEN ONE IS RESIDENT" (http://www.iium.edu.my/deed/hadith/muslim/004a_smt.html)

I was little bit confused on combining prayer when NOT in Fear and Not in Journey..
But I understood that
"Permission to join prayers is broader than permission to shorten them, because shortening them is allowed only to travelers, but both travelers and non-travellers are permitted to join prayers when it will be difficult to perform the second prayer, whether on time or in congregation".
Reference:  http://islamqa.com/en/ref/20017/travel%20prayer

Also I found the scholar opinion in http://www.ahlalhdeeth.com/vbe/showthread.php?t=3235:

Ibn `Abbas said: "Allah's Messenger (peace be upon him) combined between the Zuhr and `Asr prayers and between the Maghrib and `Isha' prayers in Madinah without there being rain nor fear." [Sahih al-Bukhari (510) and Sahih Muslim (1151)]

The ruling I follow now is that it is permissible to combine prayers if there is hardship, so long as one does not do so habitually. Scholars who agreed with this position include Ibn Sirin, Ibn Shubrumah, the Maliki jurist Asshab, the Shafii jurist Ibn al-Mundhir, and our very own Ibn Baz [ra] and Ibn Taymiyyah [ra].

Ibn Taymiyyah [ra] wrote:

    Ibn `Abbas was not traveling nor was there any rain, but he mentioned this narration as justification for combining his prayers. He knew that there was no rain, but Ibn `Abbas was involved in something important for the Muslims as he was teaching the people what they needed to know about their religion and he believed that if he stopped at that time and came down from the pulpit, the opportunity would be lost. He deemed that the activity he was engaged in permitted him to combine prayers as the Prophet (peace be upon him) combined prayers in Madinah without there being fear or rain but for some other necessity…

    All the hadith indicate that he combined prayers to make things easy for his people. Therefore, combining prayers is permissible if otherwise there would be some hardship that Allah had lifted from His nation. Combining prayers due to debilitating illness is all the more permissible. The same applies to the one who cannot maintain his purity for two prayers, like the woman whose bleeding continues past her menstrual cycle and the like. At the same time, we have a saying from `Umar b. al-Khattab that combining of two prayers without an excuse is one the grievous sins."

    [Ibn Taymiyah, Majmu` al-Fatawa]

Sheikh Sulayman al-`Isa comments on what Ibn Taymiyyah [ra] said:

    I hold the opinion that this last saying is the best. It is permissible to combine prayers in case of need, but this should not be taken as a habit. This is also the opinion of Ibn Taymiyah...

    The saying of Ibn Taymiyyah on this issue is correct in my opinion. It is permissible to combine between prayers for a valid reason, but this should not be taken as a habit. Whoever combines prayers without a valid reason and continues to do on the basis of Ibn `Abbas' hadith has violated the Sunnah of our Prophet (peace be upon him) and gone against his guidance.

    Sheikh Ibn Baz, in his marginal notes on Fath al-Bari, writes: "The best way to view the hadith is to understand that the Prophet (peace be upon him) combined between the said prayers particularly that day for some hardship, whether it was sickness, extreme cold, mud or something else. Ibn `Abbas, when he was asked about the reason for combining prayers, said it was to remove hardship from the people, which is a proper and correct answer."

    [Fath al-Bari, (2/24)].